india

Updated: Dec 20, 2018 21:46 IST

Indians would have lived 4.3 years longer if the 2016 air quality met the World Health Organisation’s (WHO) annual safe air quality guideline of 10 micrograms per cubic metre, according to a report that uses satellite measured PM 2.5 concentration trends.

Particulate pollution reduces average life expectancy by 1.8 years globally, making it the “greatest global threat to human health, said the Energy Policy Institute at the University of Chicago report. In comparison, smoking lowers global average life expectancy by 1.6 years, alcohol and drugs reduce life expectancy by 11 months; unsafe water and sanitation by 7 months; HIV/AIDS by four months, and conflict and terrorism take off 22 days.

India is second to Nepal, which recorded the highest PM 2.5 concentration globally in 2016, and a consequent decline of 4.4 years in life expectancy, said a report on the effect of air pollution on life expectancy in different parts of the world.

In comparison, life expectancy in China was cut short by 2.9 years less and by 0.1 years in the US. China’s particulate pollution declined by 12% between 2013 and 2016, resulting in a life expectancy increasing by 0.5 years, while reductions since 1970 led to US residents living 1.5 years longer.

Satellite-measured PM 2.5 concentration trends for around 670 districts in India from 1998 to 2016 show air pollution levels have increased in most districts, with the worst pollution levels being recorded in 570 districts between 2014 and 2016, which was the most polluted year for India since 1998.

In many districts, air pollution levels have more than doubled since 1998, with districts in Uttar Pradesh, Haryana and Bihar showing a steep rise in PM 2.5 concentrations between 2014 to 2016. Over the past two decades, PM 2.5 concentrations increased by 69% across the country.

“These trends need to be examined in detail on whether there was a sudden spike in recent years in some districts. The general air pollution trend is showing an increase. We didn’t have any national scale policy on reducing air pollution in a time bound manner. In Delhi, CNG was introduced for public transport in the late 90s, but with population rise, there must have been a huge rise in anthropogenic sources of pollution,” said Sagnik Dey, associate professor at Centre for Atmospheric Sciences in IIT-Delhi.

University of Chicago economists Michael Greenstone and Claire Qing Fan, co-authors of the report use 20 years of satellite derived annual PM2.5 concentration estimates for the study sourced from another global satellite and modelling based study by A Van Donkelaar.

Excluding natural sources of emissions such as dust and sea salt, the estimates use emissions generated from human activity like industry, power plants and vehicles, which leads to a marginal under-reporting in PM 2.5 concentrations compared to other reports.

The district-wise estimates dispel a few myths about India’s air pollution problem, such as Delhi has the worst air quality. Delhi recorded the 11th highest PM 2.5 levels in 2016 leading to a loss of 10 life-years for an average resident. When PM 2.5 concentrations are assessed state-wise, Delhi leads, followed by UP, Haryana and Bihar.

The 10 districts with the worst air quality in 2016 were all in Uttar Pradesh, led by Hapur.

District-wise data shows 35 districts in India met the WHO guidelines in 1998, but it was reduced to only nine districts in 2016. Globally too, average PM 2.5 levels rose by 7.8 micrograms per cubic metre between 1998 and 2016, reducing in life expectancy by about nine months.

China, India, Indonesia, Pakistan, Nigeria and Bangladesh recorded a substantial increase between 1998 and 2016, while UK, France, Germany, Mexico, Brazil and US recorded a reduction in air pollution levels during this period.