Oct AQI review: With 7 days in 'very poor' category, 2022 worse than 2021

The air quality in the national capital was in the 'very poor' category for 7 days as against zero last year. The AQI was in the 'poor' category for 10 days as against seven in 2021

Despite a prolonged spell of rain in early October, Delhi witnessed worse air quality as compared to the previous year. The air quality in the national capital was in the 'very poor' category for 7 days as against zero last year.

The city registered air quality in the ‘poor’ category for 10 days as against 7 in 2021. However, in 2020 there were 9 ‘very poor’ and 16 ‘poor’ category days.

The capital recorded an average Air Quality Index (AQI) of 210, the best in the month after the average AQI of 173 recorded in October last year.

The average AQI stood at 265 in 2020, 234 in 2019, 268 in 2018, 285 in 2017, 271 in 2016 and 264 in 2015.

An AQI between 0-50 is considered ‘good’, 51-100 ‘satisfactory’, 101-200 'moderate’, 201-300 ‘poor’, 301-400 ‘very poor’, and 401-500 ‘severe’. Above 500 is the ‘severe-plus or emergency’ category.

The city recorded two ‘good’ air quality days, the highest in 8 years, and four ‘satisfactory’ days in October owing to bountiful rainfall.

Delhi logged 128.2 mm of rainfall, the highest for October since 1956. The rainfall suppressed farm fires and kept the air clean till October 15. On October 10, Delhi recorded a 24-hour average AQI of 44, the best since August 31, 2020.

The city did not record any ‘good’ air quality day in October from 2015 to 2020.

However, pollution levels rebounded amid unfavourable meteorological conditions in the second half of the month. Emissions from firecrackers and stubble burning pushed the air quality in the ‘very poor’ category on Diwali.

The AQI has largely remained in the ‘very poor’ zone since then.

According to the Indian Meteorological Department (IMD) forecast, the air quality is likely to deteriorate and remain in the ‘severe’ category from Tuesday. The outlook for the subsequent 6 days is likely to remain largely in the ‘severe’ to ‘very poor’ category.

Stubble-burning cases in the northern states have increased by 8 per cent from the previous year. A total of 19,920 burning events were detected in the six states — Punjab (16004), Haryana (1995), Uttar Pradesh (768), Delhi (5), Rajasthan (318 ) and Madhya Pradesh (830) — from September 15 to October 31.

Residue-burning incidents saw an increase of 20 per cent in Punjab from the previous year.