Air pollution has shortened the average Indian life expectancy by 5.2 years, suggests a new report produced by the Energy Policy Institute at the University of Chicago (EPIC). The same report said that if pollution were reduced to meet the WHO guidelines, residents of Delhi could see 9.4 years added to their lives. The World Health Organisation guideline stipulates that PM2.5 does not exceed 10 micron per cubic metre and that PM10 does not exceed 20 micron per cubic metre. In India, the average PM2.5 concentration in 2018 was 63 micron per cubic metre. Lucknow was seen to have the highest level of pollution in the country, with pollution 11 times greater than the WHO guideline. Four countries that account for nearly a quarter of the world's population -- Bangladesh, India, Nepal and Pakistan -- are also among the most polluted, with northern India emerging as the most polluted part of South Asia, the report noted.