The Environment Ministry will hold a meeting on Tuesday with officials of Delhi, Punjab, Haryana and Uttar Pradesh to review the steps taken to address air pollution.

“The Minister [Bhupender Yadav] already had meetings with officials from the Central Pollution Control Board and will also have a meeting tomorrow [on Tuesday],” a spokesperson for the Ministry confirmed.

Given varying meteorological conditions, different sources of pollution gain prominence.

When wind speeds are over 10-15 kmph and temperatures are warm, fine particulate matter rises and is easily flushed out to the higher recesses of the atmosphere but with the reduction of this so-called mixing height post monsoon, pollutants take much longer to disperse.

The entire Indo-Gangetic plain, that traverses large parts of Delhi, Haryana, Punjab and eastern Uttar Pradesh, constitutes an air shed, meaning that roughly the same atmospheric conditions prevail. Therefore, when adverse weather prevails, the effect of key sources of particulate matter pollution — road dust, vehicle exhaust from transportation, from the burning of wood for heat and cooking and from heavy industry — that are ever present through the year become amplified.

During this Deepavali, however, a change in wind direction also increased the contribution of particulate matter from stubble fires in Punjab and Haryana and a new variable, crackers. Moreover farm fires from Punjab and Haryana peaked in the week gone by with little reduction, contrary to claims by bodies such as the Commission for Air Quality Management last month that there would be reduced impact from agricultural fires this year.