City air quality sees a dip as chill sets in

Box: How it is categorised

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AQI Category Impact on health

0-50 Good Minimal impact

51-100 Satisfactory Minor breathing discomfort to sensitive people

101-200 Moderate Breathing discomfort to people with lung, heart disease

201-300 Poor Breathing discomfort to people on prolong exposure

301-400 Very poor Respiratory illness to people on prolonged exposure

401-500 Severe Respiratory effects even on healthy people

Box: Recent recordings

Day AQI Category

November 1 131 Moderate

November 2 128 Moderate

November 3 155 Moderate

Dushyant Singh Pundir

Tribune News Service

Chandigarh, November 4

The air quality has worsened in the city as the Air Quality Index (AQI) slipped to ‘poor’ level for the first time this season today.

According to the Central Pollution Control Board, the AQI shot up to 203 for PM2.5 pollutants at 4 pm at the Sector 25 Air Quality Monitory Station.

Debendra Dalai, Member Secretary, Chandigarh Pollution Control Committee, said the AQI was calculated on the basis of average concentration of pollutants measured over 24 hours. The average AQI of Wednesday would be out tomorrow, he said.

He said the air quality deteriorated due to a drop in the temperature and blowing of winds, which carry pollutants from one place to another. Human-induced factors such as vehicular pollution also increased the pollution levels, he added.

He said the AQI was recorded at 155 on November 3, 128 on November 2 and 131 on November 1.

The average AQI in October remained ‘moderate’, he said.

September witnessed major changes in the AQI from ‘good’ in the first week to ‘satisfactory’ in the second and third weeks. In August, the AQI remained ‘good’, despite gradual opening of commercial activities in the city.

An AQI between 0 and 50 is classified as ‘good’, 51 and 100 as ‘satisfactory’, 101 and 200 as ‘moderate’, 201 and 300 ‘poor’, 301 and 400 ‘very poor’ and 401 and 500 ‘severe’.

Dalai stated that there had been effective improvement in the ambient air quality of the city during the lockdown period when rigorous travel restrictions had been imposed. The AQI was largely under the ‘satisfactory’ category in the week before the start of the lockdown period when compared to the progressive days where the AQI shifted to the ‘good’ category.

“This change can be attributed to restricted industrial and commercial activities, minimal vehicular congestion and zero construction activities,” he said.

A similar decline could be seen in May, but due to partial opening of lockdown, the air quality could be generally seen as ‘satisfactory’, he said.

Experts said residents were not likely to get any relief in the coming days as the period between mid-October and Diwali was considered critical in a fight against air pollution. The air also became still and heavy with the weather turning cold during this period, they said.