KOLKATA, Dec. 19: Central Pollution Control Board (CPCB) officials said steps should be taken immediately to check the rising pollution level in the city.

They were speaking at a two-day national seminar on pollution prevention and waste minimisation of small scale industrial units in the city this morning. The seminar was organised by the state Pollution Control Board (PCB).

They said the city’s pollution level had gone up because of the failure to phase out vehicles that are more than 15 years old. These vehicles emit smoke that contain hazardous gas and chemicals. The coal-based boilers of many small and medium-size plants also cause pollution by adding respirable particles in the air. These elements cause several health hazards, most common among them being asthma.

Small industries which are causing pollution include sponge iron, coke oven, stone crasher, lime kiln and ceramic factories and other coal-based units.

Forty per cent of air pollution is caused by small industries. Sponge iron plants, concentrated in Asansol-Raniganj-Durgapur belt in the state, discharge huge quantity of pollutants in the air.

Member secretary of the CPCB Mr B Sengupta said: “To bring down the pollution level, coal-based units must switch over to gas and vehicular emission must be held in check.”

State pollution control board officials said 90 per cent of the small industries located around the city had switched over from coal-based boilers to oil-based ones and part of the funds for this programme had been provided by India-Canada Environment Facility.