None of these cities, which are monitored by the Central Pollution Control Board, had good air quality between October 22 and 29

Air quality in cities in south India like Thiruvananthapuram, Chikkaballapur and Tirupati declined from “good to satisfactory and moderate” in the last week. Credit: Getty Images

Contrary to perception, it was not just North India that was breathing polluted air in the last week of October. An analysis of data by the Central Pollution Control Board (CPCB) shows that apart from Delhi and cities in Uttar Pradesh – Lucknow and Kanpur– cities across India were reeling from polluted air.

According to CPCB’s daily AQI bulletin that covers around 70 cities, almost all cities from north to south indicated deteriorating air quality.

From October 22nd to 29th, none of the 70 cities breathed “good quality air”. This is when clean air has been deemed a human right by the World Health Organization and the onset of winter is likely to further deteriorate air quality.

Moreover, air quality in cities in south India like Thiruvananthapuram, Chikkaballapur and Tirupati declined from “good to satisfactory and moderate” in the last week.

While public attention remains focused on metropolitan cities and north India due to an extremely high air pollution level, especially particulate matter, even relatively lower levels of pollutants can harm the health of those in smaller cities. In fact, the CPCB's advisory mentions that satisfactory and moderate air quality have serious health implications, especially for pregnant women, children and the elderly.

Even ‘satisfactory’ level of air quality can cause minor breathing discomfort and moderate air quality can cause breathing discomfort to those with asthma and heart diseases.

From good to moderate

Surprisingly, even for Thiruvananthapuram that was the cleanest city in October, air quality was good but only on 12 out of 31 days. Thiruvananthapuram in Kerala registered good quality air during first three week of this month, but even this deteriorated to satisfactory and moderate levels during 24th-31st October.

Besides, ambient air quality is monitored 3-5 metres above the ground and the breathing zone for humans is quite close to the ground.

Vivek Chattopadhyay, programme manager with clean air unit, Centre for Science and Environment, a Delhi-based environmental non-profit, says that it is prudent to ensure a strategy that is specific to source as well as pollutant as sources of pollution and the pollutants change as per location. For instance, in a traffic-congested area, carbon monoxide levels, No x , PM could be higher but in an industrial area, the levels of volatile organic compounds, industrial flue gases and SO 2 can be higher.

The CPCB bulletin comes as a warning to city regulators against complacency. Although southern cities may seem to fare better than rest of the cities monitored under the Air Quality Index bulletin, city regulators should always aim for global AQI standards, such as guidelines by the World Health Organization that are much more stringent than CBCB’s standards.