According to a recently released  World Air Quality Report for the year 2021, Delhi tops the list of most polluted cities, while Hydrabad is the new entry among top four most polluted cities.  IQAir, a Swiss-based air quality technology company, in its recent report found that during the year 2021, Delhi was found to be the worst polluted city in India followed by Kolkata, Mumbai and Hyderabad.

While, the top three were already known pollution hubs, Hyderabad’s entry in the list raises concern as it is now most polluted mega city in the southern part of the country.

With rise in PM 2.5 levels from 34.7 micrograms per cubic metre of air in 2020 to 39.4 in 2021, the air pollution level in the city was categorized unhealthy with the Air Quality Index (AQI) of 159, according to the data on IQAir website on October 21.

The main pollutant was Particulate Matter (PM) 2.5 or small particles with the primary sources of this being automobiles and industries. Analysts say vehicles contribute one-third of the air pollution in the city.

PM2.5 concentration in Hyderabad was 70.4 micrograms per cubic metre of air. This was 14.1 times the World Health Organisation (WHO) annual air quality guideline value.

Experts have attributed vehicular pollution as the single biggest reason for deteriorating air quality in Hyderabad in addition to fossil fuel burning, construction, opening landfill burning and landfill fires of solid waste

Like many other cities in India and the world, Hyderabad failed to meet the WHO air quality criteria of 5 micrograms per cubic metre of air.

According to healthcare practitioners small particles pose the greatest risk to human health. While the nose can filter most coarse particles, fine and ultrafine particles are inhaled deeper into the lungs where they can be deposited or even pass into the bloodstream.

The PM 2.5 level in the city had declined between 2017 and 2020 and this was attributed to green drive and strict automobile emission norms. However, the report noted that it began to rise in 2021.

The report revealed that while the average PM 2.5 during 2021 was 39.4 micrograms per cubic metre of air, it touched as high as 68.4 during December. July was relatively better with PM 2.5 hovering in the 12 micrograms per cubic metre of air range. However, even this is twice the value of 5 the permissible limit set by the WHO.

The pollution level of various Indian cities were analysed between November 20, 2020 to November 20, 2021 and the results were compared with both the prescribed air quality standards as referred by WHO and National Ambient Air Quality (NAAQS).

The report found that in terms of PM2.5, Hyderabad had an annual average of a little over 40 points, higher than NAAQS and WHO annual standards which are at 40 points and 5 points respectively. In terms of PM 10, the city had an annual average of 75 to 80 points. The NAAQS and WHO annual standards suggest this pollutant must not exceed 60 points and 15 points respectively.

(With Inputs From IANS)