Kolkata air: Worry over unhealthy AQI levels for entire January, respiratory infections surge
Telegraph | 3 February 2025
The city did not have a single day in January when the air quality was “good” or “satisfactory”, the air quality report of Calcutta shows.
The report is available on the website of the West Bengal Pollution Control Board.
Ballygunge, the upscale south Calcutta neighbourhood, was the worst among the six air quality monitoring stations in Calcutta with 17 days of “poor” air quality. Fort William was second with nine days of “poor” air quality and Jadavpur was third with eight days.
Doctors said they witnessed a surge in respiratory infections during December and January. The surge continues. An infectious disease specialist said foul air weakens the natural defense mechanism of humans, making them vulnerable to infections.
For people with chronic obstructive pulmonary disease (COPD) and asthma, the foul air can exacerbate the symptoms and even lead to hospitalisation, said Chandramouli Bhattacharya, an infectious disease specialist at the Peerless Hospital. “It can also result in coming back of symptoms in those who suffer from allergic rhinitis, but had been without any symptom for last several months,” he said.
The Telegraph analysed the air quality data for January available on the website of the West Bengal Pollution Control Board.
The report for the city — an average of the readings in all six stations within Calcutta municipal area — showed that out of 31 days in January, there were six days when the air quality was “poor”. It was “moderate” on 25 days.
The National Air Quality Index, prepared by the Central Pollution Control Board, mentions that the “possible health impact” of “poor” air quality is “breathing discomfort to most people on prolonged exposure.” The Index mentions that the impact of “moderate” air quality is “breathing discomfort to the people with lungs, asthma and heart diseases.”
The six grades of air quality in the Air Quality Index in descending order are Good, Satisfactory, Moderate, Poor, Very Poor and Severe.
The air quality of Calcutta could not go up to “good” or “satisfactory” on a single day in January.
According to the Index, “good” air quality has “minimal impact” while “satisfactory” air quality can result in “minor breathing discomfort to sensitive people.”
“This is better than the situation in Delhi or the National Capital Region or much of the Indo-Gangetic plains, but not the benchmark we should aspire for,” said Anumita Roy Chowdhury, an air quality management expert and the executive director of New Delhi-based Centre for Science and Environment (CSE).
A senior scientist of the state pollution control board admitted there was still scope for improvement, but added the air quality in Calcutta was better than what it was a few years back. “The situation was worse three or four years back. There would have been more ‘poor’ days and some ‘very poor’ or severe’ days then,” said the scientist.
An analysis of the Air Quality Bulletin, which gives a break-up of the readings in all six stations, showed that Ballygunge left others far behind in the race for the worst spot in January with 17 “poor” days.
Roy Chowdhury said that locational variation meant there were local sources of pollution that needed to be addressed. The air quality monitoring station in Ballygunge is inside the campus of the Birla Industrial and Technological Museum on the leafy Gurusaday Road.
“The primary cause seems to be vehicular pollution. There is hardly any industrial activity in Ballygunge. Many eateries in the area too could be responsible and the emissions from individual homes might add to the overall air quality,” said the state PCB scientist.
Sibes Kumar Das, the head of respiratory medicine at Medical College, Kolkata, said the department witnessed aoriund 25 per cent surge in the number of patients during December and January. “Asthma and COPD symptoms exacerbate and new patients also come with complaints of respiratory problems,” he said.
The World Health Organisation (WHO) estimated that “ the combined effects of ambient air pollution and household air pollution are associated with 6.7 million premature deaths annually.”