SO₂ emissions spike in Hyderabad, IIT Kanpur study flags vehicle, industry role

HYDERABAD: A study commissioned by the Pollution Control Board and conducted by IIT Kanpur has flagged a sharp surge in sulphur dioxide (SO₂) emissions across Hyderabad and its outskirts, pointing to vehicles and industries as the main contributors.

According to the study, the Outer Ring Road (ORR) region recorded SO₂ emissions of 18,101 kg per day, while the Greater Hyderabad Municipal Corporation (GHMC) area logged 10,701 kg per day.

Vehicles dominate GHMC sulphur dioxide load

Within GHMC limits, vehicles accounted for 91% of SO₂ emissions, the report said. In contrast, industries contributed 92% of the emissions in the ORR belt, highlighting the differing pollution sources across zones.

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The study found that air pollution sources together contributed 33% of particulate matter (PM10) emissions, with the remaining load arising from non-PM10 pollutants, including sulphur dioxide.

Sulphur dioxide, produced mainly through fossil fuel combustion, is linked to acute respiratory problems such as throat irritation, airway inflammation, aggravated asthma and reduced lung function. When it reacts with moisture, it forms acid rain, posing risks to ecosystems, crops and infrastructure.

Titled “Best available techniques and uptake of cleaner fuels for minimising emissions”, the study covered five representative locations: Datta Nagar and Narayanguda (residential), IDA Jeedimetla (industrial), University of Hyderabad (background), Charminar–Ghansi Bazar (commercial) and Zilla Parishad High School, Uppal. The sites span municipal, GHMC and ORR zones to map citywide pollution patterns.

Source apportionment showed industries as the largest PM10 contributor at 33%, including 5% direct and 28% indirect emissions. Secondary Inorganic Aerosols contributed 8%, vehicular sources 5% and road dust 15%.

For non-PM10 pollutants, industry-related volatile organic compounds (VOCs) accounted for 66%, sulphur dioxide for 91% and nitrogen oxides (NOx) for 10%. VOCs arise from solvents, paints, coatings and chemical processes, while NOx from high-temperature combustion contributes to smog, acid rain and ground-level ozone.

The report recommended stricter emission standards, noting that many countries enforce limits below 30 mg/Nm³, compared to the current 100–500 mg/Nm³. It also suggested expanding piped natural gas usage and relocating heavily polluting industries away from densely populated urban areas.