A global analysis of how nations tackle environmental challenges has ranked India 155 among 178 nations and labelled the country’s air quality among the worst in the world, tying it with China in exposing its population to hazardous air pollution.

The Environmental Performance Index 2014, generated by researchers at Yale University in the US, has bracketed India among “bottom performers” on several indicators such as environmental health impact, air quality, water and sanitation.

Compared with EPI 2010 — when India ranked 123 among 163 countries — the rank of 155 now among 178 countries suggests that the country’s position has worsened since then. Fifteen countries were added since 2010 but India’s position fell by 32 notches.

The EPI 2014 report, released in Davos, Switzerland, on Saturday, comes amid what some environmental researchers in India say are independent signals that China has been moving to curb the threat of air pollution through policy measures a lot faster than India.

“Although India is an emerging market alongside Brazil, China, Russia and South Africa, its environment severely lags behind these others,” Angel Hsu, the lead author of the report at Yale University said in a media release.

The EPI 2014 has ranked Switzerland at the top.

The researchers said urbanisation without adequate investments in environmental protection may help explain why India has experienced “a 100 per cent decline” in some air quality scores over the past decade.

The EPI 2014 report has ranked India’s air quality — measured in terms of fine, inhalable particulate matter (PM) less than 2.5 millionths of a metre in size — at 177, with only China in the last position.

But the non-government Centre for Science and Environment, New Delhi, said data from India’s Central Pollution Control Board and the Beijing Environmental Protection Bureau suggest that China has taken aggressive policy steps to curb air pollution.

The CSE said the levels of PM 10 (particulate matter between 2.5 millionths of a metre to 10 millionths of a metre) in Beijing declined by 40 per cent from 2010 to 2013. PM10 levels in Delhi are nearly double that of Beijing, and increased 47 per cent from 2010 to 2011.

“China has shown how air quality can be improved through aggressive action — there are lessons in this for India,” said Anumita Roy Chowdhuri, deputy director of environmental pollution at the CSE.

The local Beijing government, she said, has imposed a cap on the number of cars that can be sold in a year to 240,000 which is likely to be further reduced to 150,000. When air pollution increases, local authorities impose restrictions on the use of private cars.

“Both vehicles and construction activity have been contributing to the rising PM levels in Indian cities,” said Bhola Ram Gurjar, a civil engineer at the Indian Institute of Technology, Roorkee, who has been monitoring air pollution levels across the country for nearly a decade. Local governments in China also have to pay a fine if air pollution levels rise beyond a critical limit. China does not allow a sharp difference between petrol and diesel prices. Diesel cars in Beijing account for only one per cent of private vehicles, compared with half in Delhi.

“There has been enormous public pressure in China that has made the government act,” Roy Chowdhury said. “For some reason, despite long-standing campaigns for clean air, we don’t see the same level of public demand for cleaner air in India.”

The EPI assesses nations on several environment-linked issues such as air quality, health impacts of environmental pollution, water and sanitation, conservation of biodiversity and habitats, agriculture among others. The 2014 report said India does relatively better on forests, fisheries, and water resources than in other areas.