Smog in north spikes air pollution in southern cities
Pollution spikes are common in the first half of November in northern India as farm fires peak in Punjab and Haryana during this time and the resulting smoke settles over the region.Updated: Nov 07, 2019, 13:27 IST
There was a spike in air pollution levels in eastern and southern India on Thursday with the Air Quality Index (AQI) in some parts of Chennai rising over 300. Officials said that this was primarily because winds were carrying pollutants from the northern plains towards the Bay of Bengal.
A Central Pollution Control Board (CPCB) official, who did not want to be named, said that north-westerly winds have blown the smoke created because of stubble burning in Punjab and Haryana from the northern plains because of a developing cyclonic depression over the Bay of Bengal.
Pollution spikes are common in the first half of November in northern India as farm fires peak in Punjab and Haryana during this time and the resulting smoke settles over the region. Farmers often burn stubble left behind after harvest as a quick and cheap way of clearing their fields for the next round of sowing.
The air quality in Delhi was reduced to its worst level since 2016 on Sunday as the AQI sharply rose to a severe level of 494.
Severe air pollution can worsen existing respiratory illnesses and also affect even healthy people.
The CPCB’s real-time monitor showed the AQI crossing the 300-mark in some parts of Chennai. The air quality is considered good when the AQI is below 50 and satisfactory when it is under 100.
The AQI in Andhra Pradesh’s Visakhapatnam and Vijayawada rose to 274 and 204. The AQI in Kolkata was 262. The pollution levels dipped in Bangalore with the AQI being 157.
An India Meteorological Department (IMD) official said that the cyclonic storm, which is expected to make landfall on Friday, is preventing pollutants from dispersing over the Bay of Bengal as it is moving towards the eastern coast.
“In fact, strong inward winds from… [the Bay of Bengal] have pushed the winds carrying the smoke towards south from eastern India…,” an IMD scientist said.
The CPCB scientist quoted above said that the pollution levels in southern and eastern cities have also increased because of local factors apart from the winds carrying the particulate matter.
The scientist added the situation is likely to improve in a day or two as fresh winds will bring cleaner air. The impact of the depression in the Bay of Bengal will also end with heavy rains, which is also expected to bring some respite, the scientist added.
Officials said that unlike in the northern Indian plains, the air pollution monitoring in eastern and southern India, considered to be comparatively cleaner, is less common. For instance, Kolkata has only three monitoring stations, Chennai four and Visakhapatnam one.
According to pollution forecast and data website airvisual.com, the north-westerly winds were moving the pollutants towards the east and then to southern India along the east coast.
Experts, too, blamed the farm fires’ smoke for the rise in pollution levels in eastern and southern India. “The Atmospheric Dispersion Modeling System [used to calculate concentrations of pollutants] shows that the plumes of the smoke have reached southern India,” said Raj Bhagat Palanichamy, a remote sensing analyst with research organisation the World Resources Institute.
The rising pollution prompted Bihar chief minister Nitish Kumar on Wednesday to order the phasing out of diesel and old petrol autos. He also ordered a revamp of the public transport system as the AQI in Patna reached 414 on Wednesday and came down to 347 on Thursday, which still comes under the “very poor” category.