On Friday, India's Central Pollution Control Board (CPCB) ordered states and local bodies to be in "complete readiness" for Delhi's smog condition to worsen in the next few days because there has been a drop in both temperature and wind speed. According to the CPCB, the Air Quality Index (AQI) in Delhi hit 470 on a scale of 500 on Friday afternoon.
"Government and private offices are advised to reduce vehicle usage by 30 percent," the board said, adding that the city's residents should limit how much time they spend outdoors.
"Meteorological conditions will be highly unfavourable for dispersion of pollutants until 18 November in view of low winds with calm conditions during the night," the board added.
The CPCB said that should the air quality remain in a "severe" category for 48 hours, local authorities should introduce emergency measures such as shutting down schools, vehicle rationing, and stopping all construction.
In its first large-scale study, released by the CPCB on Friday, it was found that crop residue burning (CRB) contributes to the high particulate matter (PM) concentration in ambient air in Delhi and its surroundings.
"The decline in lung function with an increase in PM2.5 concentration (during CRB days) was noted across all age groups even after controlling for several other exposure variables, ie, cooking fuel, ventilation, distance from roads, etc," the study found.
According to a recent report by the Ministry of Agriculture and Farmers' Welfare, nearly 30 million metric tons of paddy straw are created in the northern states of Punjab and Haryana, and about 23 million metric tons were burnt in the field as an easy and quick method of disposal.
The federal government has made generating pollution by burning stubble a punishable offence with a jail term of up to five years and a fine of up to INR10 million ($135,000).