In 2025, the world’s cleanest countries are not just global leaders in environmental health—they are also innovators in climate policy, renewable energy, and sustainable development. These nations have earned top rankings through rigorous assessment by the Environmental Performance Index (EPI) and the Climate Change Performance Index (CCPI), which together provide the most authoritative and data-driven evaluations of national environmental performance.

The EPI, developed by Yale and Columbia Universities, uses 58 indicators across 11 categories—ranging from air and water quality to biodiversity and climate policy—to rank 180 countries on how well they meet sustainability targets. The CCPI, meanwhile, evaluates 63 countries and the EU, covering over 90% of global greenhouse gas emissions, and assesses performance in GHG emissions, renewable energy, energy use, and climate policy.

These indices are vital tools for policymakers, businesses, and communities, offering a granular view of each country’s strengths and weaknesses, helping to set targets, track trends, and identify best practices for a sustainable future. High-ranking countries benefit from advanced regulatory frameworks, greener infrastructure, and new market opportunities for sustainable technologies. Here’s a closer look at what sets each of the top 10 apart in 2025:

1. Estonia (EPI Score: 75.3)

Estonia leads the world in cleanliness and sustainability, thanks to its extensive forest cover, effective use of bioenergy, and a strong focus on natural resource management. The country has set ambitious climate goals, including a 70% reduction in greenhouse gas emissions by 2030 and carbon neutrality by 2050.

Estonia achieved an 11.3% emissions reduction in late 2024, outpacing the rest of the EU, even as its economy grew. The capital, Tallinn, has become a beacon of urban sustainability, winning the ITB Earth Award 2025 for its zero-waste Song and Dance Celebration, which drastically cut single-use plastics and promoted circular economy practices.

Estonia’s environmental policies have also led to Europe’s cleanest air and ongoing investments in wind, solar, and energy storage. However, the country faces challenges in fully phasing out fossil fuels and balancing biomass production with forest conservation.

2. Luxembourg (EPI Score: 75.0)

Luxembourg stands out as a small nation with outsized environmental achievements, earning an EPI score of 75.0 in 2024 and a 4.1-point rise over the past decade. The country leads the world in water management, boasting a near-perfect score of 90.6 in Water Resources and an astounding 99.8 in Sanitation & Drinking Water. Over 55% of Luxembourg’s land is protected, contributing to a top-tier biodiversity score of 84.8.

The nation’s capital has pioneered green investments, while advanced wastewater treatment and strict EU-aligned standards keep pollution low. While Luxembourg excels in ecosystem vitality and heavy metal pollution control, it continues to work on reducing per capita greenhouse gas emissions and curbing tree cover loss.

3. Germany (EPI Score: 74.6)

Germany ranks third globally with an EPI score of 74.6 in 2024, marking a 4.4-point improvement over ten years. The country treats 100% of its urban wastewater, achieving a high 89.1 in Water Resources, and protects a significant share of its land and seas, reflected in its 82.4 Biodiversity & Habitat score.

Germany’s robust environmental policies are complemented by massive investments in green infrastructure and renewable energy. The nation’s cities are recognized for clean air, efficient public transport, and progressive urban planning. Germany’s approach demonstrates that sustainability can go hand in hand with industrial progress, though ongoing industrial emissions remain a challenge.

4. Finland (EPI Score: 73.7)

Finland secures the fourth spot with a 2024 EPI score of 73.7, though this reflects a slight decrease from its 2014 score. The country is a global leader in public health, scoring a perfect 100.0 in both Sanitation & Drinking Water and Heavy Metals. Finland’s well-managed forests, protected natural areas, and clean air contribute to its strong ecosystem vitality.

The nation’s deep cultural connection to nature is evident in its policies, which seamlessly integrate sustainability into daily life. Finland’s challenge lies in maintaining its high standards amid growing urbanization and climate pressures.

5. United Kingdom (EPI Score: 72.7)

The United Kingdom earns an EPI score of 72.7 in 2024, up by 2.1 points over the past decade. The UK has made significant progress in reducing carbon emissions, largely through aggressive wind energy deployment and expanded recycling programs. Urban green spaces and biodiversity conservation have improved city livability and environmental health.

The UK continues to update its climate policies to meet international targets, but faces ongoing challenges with air quality in some metropolitan areas and the need for further emissions reductions.

6. Sweden (EPI Score: 70.5)

Sweden ranks sixth with a 2024 EPI score of 70.5, showing a modest 1.6-point increase over ten years. The country’s energy mix is dominated by hydropower and wind, and it is a pioneer in negative emissions technologies.

Sweden’s cities are models of sustainable urban development, and the nation’s commitment to clean air, water, and biodiversity is unwavering. However, Sweden faces pressure to further reduce emissions from transportation and industry to meet its ambitious climate goals.

7. Norway (EPI Score: 70.0)

Norway holds the seventh position with a 2024 EPI score of 70.0, up 3.6 points over the last decade. The country boasts nearly universal access to clean drinking water and sanitation, and its electricity is almost entirely supplied by hydropower.

Norway’s proactive climate policies and investments in electric mobility and carbon capture have resulted in some of the world’s lowest per capita emissions. The country’s challenge is balancing oil and gas exports with its climate commitments.

8. Austria (EPI Score: 69.0)

Austria scores 69.0 on the 2024 EPI, reflecting a slight decrease of 0.3 points over ten years. The country excels in maintaining clean cities and countryside through strict agricultural and chemical regulations. Austria’s public transport system and urban planning support eco-living, while strong environmental laws ensure high water quality and effective waste management.

Austria’s challenge is to address areas of stagnation and reinvigorate progress on climate adaptation and emissions reduction.

9. Switzerland (EPI Score: 68.0)

Switzerland earns a 2024 EPI score of 68.0, up 1.8 points over the last decade. The country is renowned for its pristine landscapes, robust waste management, and advanced water treatment systems.

Switzerland’s environmental protection laws and public engagement in sustainability initiatives help maintain high living standards and ecological health. However, Switzerland must continue to innovate in renewable energy and reduce its ecological footprint to stay ahead.

10. Denmark (EPI Score: 67.9)

Denmark rounds out the top ten with an EPI score of 67.9 in 2024, a 1.7-point increase over ten years. The nation is a global leader in wind energy and urban planning that prioritizes cycling and green spaces. Denmark’s comprehensive recycling policies and low pollution levels make it a model for clean living. 

The country’s ongoing challenge is to further cut emissions from agriculture and transportation while maintaining economic growth.

How Are These Rankings Determined?

Environmental Performance Index (EPI):

• Uses 58 indicators across 11 categories, including air quality, water and sanitation, biodiversity, habitat protection, and climate policy.
• Weights environmental health (40%) and ecosystem vitality (60%) to reflect both immediate human well-being and long-term sustainability.
• Draws data from the WHO, UN, and other global agencies, providing a scorecard for each country and highlighting leaders and laggards.

Climate Change Performance Index (CCPI):

• Assesses four main categories: GHG emissions (40%), renewable energy (20%), energy use (20%), and climate policy (20%).
• Uses 14 indicators, combining quantitative data (from IEA, FAO, UNFCCC) and qualitative expert assessments of national and international climate policy.
• Covers 63 countries and the EU, representing over 90% of global GHG emissions.

These indices are not just academic—they guide policy, inform investment, and help countries benchmark progress toward sustainability goals. High-ranking countries typically have strong regulatory frameworks, transparent governance, and engaged civil societies, making them attractive for sustainable business and investment.

Why Does This Matter?

• Policy Guidance: Countries use EPI and CCPI data to set targets, track trends, and refine environmental policies.
• Business and Investment: High scores signal a favorable environment for green investment and sustainable business operations.
• Public Health: Clean air, water, and effective waste management directly improve quality of life and reduce healthcare costs.
• Global Leadership: These nations serve as models for others striving to balance economic growth with environmental stewardship.

Summary point

As environmental challenges grow increasingly urgent worldwide, the achievements of these top 10 cleanest countries in 2025 offer both inspiration and a practical roadmap for sustainable development. Their success demonstrates that with visionary leadership, innovative technologies, and committed public participation, it is possible to safeguard natural resources, improve public health, and foster economic growth simultaneously.

By learning from their policies and practices, other nations can accelerate their own journeys toward a cleaner, greener, and more resilient future—ensuring a healthier planet for generations to come

Gisborne faced significant travel disruption on Thursday, July 31, as Air New Zealand suspended all flights in and out of the city's airport following technical issues with two of its aircraft. The airline, the sole carrier linking Gisborne to Auckland and Wellington, grounded its entire Gisborne operation after both of its de Havilland Q300 planes required urgent repairs, bringing operations to a halt that began Wednesday afternoon.

One aircraft sustained in-flight propeller blade damage, the cause of which remains unknown, while the second failed a critical cockpit control check, prompting engineers to commence maintenance work immediately. With Gisborne Airport having only two gates, both occupied by the grounded planes, no other flights could operate, leaving passengers stranded and flights canceled through much of Thursday.

The disruptions caused mounting frustration among travelers, many of whom reported receiving late flight cancellation notices and poor communication from the airline. One passenger, booked on a 6 AM flight, was not informed of its cancellation until 3 PM the previous day and faced difficulty rebooking flights that conflicted with his return schedule.

 Another passenger, traveling internationally via Auckland, learned about the disruption only upon arrival at the airport missing valuable family time due to the delayed notification.

In response, Air New Zealand expedited the delivery of replacement parts overnight and deployed engineers to Gisborne, aiming to resume flights by the evening. The airline offered alternative travel arrangements where possible, including road transport to Napier for some passengers, though limited seat availability restricted options.

 Chief Operating Officer Alex Marren thanked customers for their patience, highlighting efforts to restore services promptly and exploring additional aircraft parking at Gisborne to prevent future groundings caused by limited space.

Local leadership underscored the critical nature of reliable air service to the region. Gisborne Mayor Rehette Stoltz described Air New Zealand flights as a "lifeline" for business, family, and international connectivity. Following recent discussions with the incoming Air New Zealand CEO, Stoltz urged the airline to improve communication and service consistency, especially given Gisborne’s isolation and the airline’s majority government ownership.

The mayor also acknowledged the airline’s support during emergency responses, such as flight arrangements after Cyclone Gabrielle, expressing hope such cooperation would extend to routine operations.

This latest disruption reflects ongoing challenges for air travel in Gisborne, highlighting vulnerabilities in infrastructure and the critical importance of maintaining reliable connections for isolated communities.

Istanbul Airport has once again claimed the title of the world’s best international airport, securing the top spot in Travel + Leisure’s prestigious “World’s Top 10 International Airports” ranking for the second consecutive year.

The announcement was made by Türkiye’s Minister of Transport and Infrastructure, Abdulkadir Uraloğlu, who hailed the recognition as a “double success” for the airport. In addition to maintaining its global title, Istanbul Airport also recorded its highest-ever daily flight count on July 18, with 1,695 air traffic movements.

“This year, Istanbul Airport scored an impressive 98.57, up from last year’s 95.79,” Travel + Leisure noted, calling the achievement “extra impressive,” especially considering the airport ranked seventh just two years ago with a reader score of 83.36.

Airports in the survey were evaluated by readers based on key criteria such as accessibility, check-in experience, security procedures, dining options, shopping, and overall design. Istanbul Airport’s continued dominance reflects its rapid evolution into a global aviation powerhouse since entering the ranking in 2021 — the first Turkish airport ever to do so.

Operated by IGA, the airport has demonstrated significant operational milestones. In April, it became the first in Europe and second globally to operate three runways simultaneously, following only the United States. In 2024, it handled nearly 80 million passengers, solidifying its position as Europe’s largest and second-busiest airport, according to the State Airports General Directorate (DHMI).

Istanbul Airport is not only a leader in passenger traffic but also in air cargo. It was named Europe’s busiest cargo hub by Airports Council International (ACI) in its 2024 Annual Traffic Report. Weekly data from Eurocontrol consistently ranks it among Europe’s top airports for daily flights.

With a seamless blend of cutting-edge infrastructure, operational excellence, and world-class passenger amenities, Istanbul Airport continues to redefine global standards in aviation.

Hamad International Airport (DOH) maintained a robust and stable operational performance in the first half of 2025, reflecting its resilience amid evolving global travel dynamics. As the gateway to Qatar, the airport saw a notable increase in point-to-point travel to Doha, with passenger traffic rising by 2.3% between January and June 2025, underscoring the city's growing status as both a tourism and business hub.

During the same period, Hamad International Airport served 25.9 million passengers, marking a slight year-on-year dip of 0.45%, while cargo volumes totaled 1.2 million tonnes (-1.68% Y-o-Y), and aircraft movements reached over 136,000 (-1.71% Y-o-Y). These figures remain in line with regional trends and reflect the airport’s ability to sustain momentum despite the leap year comparison to 2024.

Beyond numbers, Hamad International Airport continued its commitment to enhancing the passenger journey. The airport’s recent expansion – including the opening of Concourses D and E – significantly boosted capacity, adding 17 new contact gates and increasing boarding bridges by 40%. These enhancements eliminated an estimated 350,000 bus transfers, streamlining terminal-to-aircraft transitions and offering a more seamless travel experience.

The terminal’s inclusive design further elevates passenger comfort, featuring barrier-free pathways, hearing loops, spacious seating areas, and dedicated services such as family lanes and e-gates for travelers with disabilities. These initiatives demonstrate the airport's focus on accessibility and thoughtful service.

Adding to its signature ORCHARD indoor tropical garden, Hamad International Airport also unveiled a permanent art collection by renowned artists Gillie and Marc. These installations not only enrich the airport’s ambiance but also serve as a reminder of the need to protect endangered wildlife, blending travel with cultural and environmental consciousness.

As it continues to evolve, Hamad International Airport stands as a model of operational excellence and passenger-centric innovation in the global aviation sector.

Riyadh’s King Khalid International Airport (KKIA) has once again achieved a major milestone, earning the distinction of being the world’s most punctual airport in June 2025 with an impressive on-time performance rate of 90.41%. This recognition was announced by Cirium, a global leader in aviation analytics, reinforcing KKIA’s reputation for operational excellence and reliability on the international stage.

Third Top Ranking in 2025

This marks the third time in 2025 that KKIA has secured the number one global ranking for punctuality, having previously attained this accolade in March and April. Such consistency underlines KKIA's commitment to maintaining world-class standards in flight operations and passenger experience.

Cirium Report and Methodology

Cirium compiles its punctuality rankings through a comprehensive analysis of data from airlines, air traffic control systems, and airport feeds across the globe. The rankings reflect the proportion of flights departing or arriving within 15 minutes of their scheduled times—a widely accepted industry standard. This robust methodology guarantees transparency and accuracy, providing a valuable benchmark for industry stakeholders and travelers alike.

Saudi Vision 2030 and Aviation Strategy

KKIA’s consistent top performance aligns with Saudi Arabia’s Vision 2030, the Kingdom’s ambitious strategy to transform its aviation sector and cement Riyadh as a top-tier logistics and travel hub. Ongoing investments in new infrastructure, enhancements in efficiency, and elevated customer service standards have all contributed to this achievement.

Additional 2025 Milestones and Recognitions

• Skytrax 2025 Awards: KKIA climbed to 24th place globally in the Skytrax World Airport Awards, an 11-position improvement, becoming the highest-ranking Saudi airport ever. The airport also received honors for “Best Airport Staff in the Middle East,” third globally for the “Best New Terminal,” and fourth for airports in the 30–40 million passengers category.

• Environmental Leadership: Earlier in 2025, KKIA became the first airport in Saudi Arabia to reach Level 4 Transformation under the Airport Carbon Accreditation program, marking a significant step toward sustainability and a commitment to reach net zero emissions by 205010.

• Expanding Connectivity: 2025 saw the launch of direct flights from Virgin Atlantic and US-Bangla Airlines, strengthening air links between Riyadh and key international destinations such as Toronto and Dhaka, further cementing KKIA's role as a global gateway.

• Domestic Excellence: KKIA maintained top rankings within Saudi Arabia for passenger traffic and flight punctuality, driven by ongoing modernization and expanded passenger services.

Saudi Airlines Also Excel

In June 2025, Saudia was named the world’s most punctual airline, with a 91.33% on-time arrival rate and a 90.69% on-time departure rate, according to Cirium. Saudia’s low-cost carrier, flyadeal, led the Middle East and Africa with a 91.77% punctuality rate, adding further prestige to Saudi Arabia’s aviation achievements.

iGA Istanbul Airport and Chicago O’Hare International Airport have formalized a Sister Airport agreement, uniting two of the world’s most prominent aviation hubs in a partnership designed to foster collaboration and innovation across multiple facets of airport operations. The agreement was signed during a ceremony at O’Hare’s Terminal 5 on June 20, 2025, attended by executives from both airports and Türkiye’s Consul General in Chicago, Tahir Bora Atatanır.

The partnership aims to facilitate joint projects in airport management, operations, customer service, planning, and sustainability, reflecting the shared commitment to advancing global connectivity and excellence in passenger experience.

Selahattin Bilgen, CEO of iGA Istanbul Airport, highlighted the strategic importance of this alliance for expanding iGA’s presence in North America and strengthening its global network. He noted that the cooperation is expected to yield mutual benefits in both passenger and cargo transportation, leveraging the airports’ roles as major international gateways.

iGA Istanbul Airport, ranked the seventh busiest in the world by passenger numbers in 2024 and the ninth by aircraft movements, serves as Türkiye’s largest airport and a major hub for Turkish Airlines, offering nonstop service to over 330 destinations—including 14 in the United States. Similarly, O’Hare is recognized as the best-connected airport in the United States and a critical hub for Star Alliance carriers.

The agreement is particularly significant given the strong business and cultural ties between Chicago and Istanbul. The Chicago metropolitan area is home to approximately 5,000 Turkish nationals, with over 20 Turkish investors and 12 Turkish firms operating in the city, while eight Chicago-based companies maintain a presence in Türkiye. This partnership is expected to further enhance trade, tourism, and cultural exchange between the two cities.

Michael J. McMurray, Commissioner of the Chicago Department of Aviation, emphasized that the Sister Airport agreement will elevate bilateral relations between the United States and Türkiye and help maintain Chicago’s status as a global transportation hub. The partnership is also supported by World Business Chicago, whose President & CEO, Phil Clement, underscored the unique position of Istanbul as a city bridging Europe and Asia, and the value of deepening international ties for Chicago’s diverse economy and global reach.

The Sister Airport agreement establishes joint working groups focused on sharing best practices in airport management, customer service, planning, operations, and sustainable development. This is iGA Istanbul Airport’s first such partnership in the Americas, complementing its existing alliances with major airports in Asia and Europe, including Incheon, Beijing, Shanghai, and Copenhagen.

For the Chicago Department of Aviation, this marks its tenth Sister Airport agreement, further expanding its international network.

Both airports anticipate that the collaboration will position them to capitalize on growing passenger and cargo volumes, reinforcing their roles as vital nodes in the global aviation network and setting a foundation for ongoing innovation and connectivity