Increase access to resilient and affordable urban services and infrastructure

Buses and trains are a crucial component of decarbonizing the transport sector. They release about a quarter as much emissions per passenger-kilometer (pkm) as ride-hailing services and about half as much as private vehicles.

This indicator measures the number of kilometers (km) of rapid transit per million people. Across the world’s 50 highest-emitting cities, rapid transit coverage increased from 16 km per million people in 2010 to 24 km in 2024. To achieve a pathway compliant with the 1.5 degrees C (2.7 degrees F) target, rapid transit in these 50 cities would need to reach 38 km per million people by 2030. This would require the pace of change achieved over the last five years to increase by 5 times.

Rapid transit — comprising metro, light rail and bus rapid transit (BRT) — represents the primary modes of sustainable mass transit in cities around the world. Globally, metro systems grew steadily between 2010 and 2023. Seventy-three urban conglomerates opened their first metro systems during this period, with China accounting for half of these launches. Between 2010 and 2022, China inaugurated a new metro line in at least one urban area every year. By 2025, India’s metro network exceeded 1,000 km across 23 cities, ranking third globally behind China and the United States.

As of 2025, BRT networks served 191 cities globally, carrying over 32 million passengers daily, with Latin America leading at 19 million daily passengers over 2,000 km of corridors. However, after two decades of rapid growth, BRT implementation has slowed in recent years.

It is important that cities provide broader support to public transport systems, including rapid transit and bus services. Policies that address informal popular transport systems, such as minibuses, are also needed.

Air pollution is the world’s leading environmental health risk factor. In 2019, about 7% of all deaths worldwide were attributable to exposure to fine inhalable particles, which is defined as particulate matter with a diameter of less than 2.5 micrometers (PM2.5). Nearly half of all exposure from fine particles is caused by unsustainable energy practices, including the combustion of fossil fuels.

Rapidly urbanizing countries in Africa and Asia have the highest levels of air pollution. This is caused by several factors, including lack of access to clean fuels for cooking and emissions from transportation and manufacturing industries. Nearly everyone in rapidly urbanizing low- and middle-income countries is currently exposed to PM2.5 levels that exceed the guidelines from the World Health Organization (WHO). Children, residents of low-income areas and Black, Indigenous, Hispanic, Asian and other communities of color are disproportionately impacted.

Sustainable Development Goal 7 aims to phase out biomass combustion for heating and cooking by 2030. If achieved, this would result in a 20% reduction in premature deaths from PM2.5 exposure as compared to 2015 levels (4.6 million), reducing the total to about 3.7 million.

Meeting three interrelated goals — the phasing out of internal combustion engines, thermal power generation (without pollution controls) and other fossil fuel combustion by 2050 — would translate to a 50% reduction in premature deaths from PM2.5 exposure as compared to 2015 levels, further reducing the total to about 1.9 million (author’s analysis). Thus, achieving reductions of 20% by 2030 and 50% by 2050 would help save millions of lives.

Unfortunately, this indicator is headed in the wrong direction, as evidenced by the continued increase in premature deaths from 1990 until 2021  resulting from air pollution. In 2020, there was a drop in premature deaths from 4.6 million in 2019 to 4.43 in 2020, likely as a result of the COVID-19 pandemic. However, in 2021, premature deaths increased again to 4.72 million. Premature deaths from PM2.5 exposure must peak immediately and fall quickly to meet the 2030 goal.

Access to electricity is vital to economic productivity and livelihoods, yet millions of urban residents around the world do not have access to clean, reliable energy.

Since 2000, the percentage of people in urban areas without access to electricity has decreased. In 2000, over 5% of urban residents lacked access to electricity; in 2022, 2.3% — still over 100 million people — did not have access.

Between 2019 and 2021, rural areas underwent rapid electrification, outpacing population growth. At the same time, progress flattened in urban areas, partly because they had already achieved higher access rates and partly because rapid urbanization had increased energy consumption and offset access gains.

Cities have a major role to play in how energy is provided and consumed, but in doing so they must face the dual challenge of expanding access to electricity while also meeting increased energy demands. Cities can improve access to clean, affordable and reliable energy by scaling up distributed renewable energy sources, such as solar.

For example, in cities in Kenya, Tanzania and Uganda, community solar has increased access to energy, while lowering costs for households. This lowers air pollution and carbon emissions.

While access to electricity has improved in the last 20 years, the world is still off track to achieve Sustainable Development Goal 7, ensuring access to affordable, reliable, sustainable and modern energy for all. Progress needs to double in urban areas and needs to be 1.9 times faster in all areas (not just urban) to reach energy access for all by 2030.