The National Green Tribunal has asked Delhi, Haryana, Uttar Pradesh, Punjab, Rajasthan and Bihar to respond to a recent World Health Organisation (WHO) report on 20 most-polluted cities in the world.
According to the WHO global air pollution database, 14 out of the 15 most-polluted cities in the world in terms of Particulate Matter or (PM) 2.5 concentrations are in India.
Kanpur, being the worst, is with a PM 2.5 concentration of 173 micrograms per cubic metre, followed by Faridabad, Varanasi and Gaya.
A bench headed by acting NGT Chairperson Jawad Rahim yesterday sought responses from the governments of these states including Delhi.
They have been asked to clarify their standby 21st May, the next date of hearing.