Heavy metals found in Delhi’s air, says CPCB in report to NGT

According to the CPCB, the average PM10 concentration during the monitoring period in Delhi was 130 micrograms per cubic metre. The average concentrations of specific metals were: copper at 55.13 ng/m³, chromium at 12.25 ng/m³, molybdenum at 0.91 ng/m³, and zinc at 243.5 ng/m³

The Central Pollution Control Board (CPCB) has informed the National Green Tribunal (NGT) that it has detected the presence of heavy metals in Delhi’s air, with concentrations of copper, zinc, chromium, and molybdenum ranging between 0.1% and 2% of the total particulate matter (PM10) concentration in the region.

The smog seen on UER-2 in Dwarka in south-west Delhi on Monday. (Vipin Kumar/HT Photo)

In a report submitted to the tribunal, the CPCB said samples were collected from Delhi and nine other cities during June and July this year. In Delhi, samples were taken from Pitampura, Siri Fort, Janakpuri, and Shahdara, according to the report uploaded on October 26.

The NGT had taken suo motu cognisance of a news report published in September last year, which cited a study highlighting the presence and rising trend of heavy metals in east Delhi’s air. The tribunal had directed the CPCB to analyse the data and submit its findings.

In its report, the CPCB said ambient air quality monitoring for particulate matter (PM10) and metals — including zinc, chromium, copper, and molybdenum — was conducted across 10 metropolitan cities: Jaipur, Bhopal, Lucknow, Ahmedabad, Nagpur, Kolkata, Bengaluru, Visakhapatnam, and Chennai.

According to the CPCB, the average PM10 concentration during the monitoring period in Delhi was 130 micrograms per cubic metre. The average concentrations of specific metals were: copper at 55.13 ng/m³, chromium at 12.25 ng/m³, molybdenum at 0.91 ng/m³, and zinc at 243.5 ng/m³. (One microgram per cubic metre equals 1,000 nanograms per cubic metre.)

At present, there is no defined standard or threshold for heavy metals in ambient air in India.