The Hindu : New Delhi News : CNG gains may be lost to rising nitrogen oxide levels

Online edition of India's National Newspaper
Monday, Jul 12, 2004

New Delhi

New Delhi

CNG gains may be lost to rising nitrogen oxide levels

By Sujay Mehdudia

NEW DLEHI, JULY 11. Expressing serious concern over the steady rise in nitrogen oxide levels in the Capital, the Centre for Science and Environment (CSE) has warned the Delhi Government that if this problem were not tackled immediately, it could sabotage one of the largest clean fuel programmes in the world. It has urged the Government to push ahead with second-generation reforms in the Capital to prevent any reverse of the situation.

Suggesting an immediate action plan for controlling nitrogen oxide emissions from vehicles, the CSE said CNG vehicles posed maintenance challenge that had to be met effectively.

Recent surveys conducted on CNG buses in Delhi have shown that on account of poor maintenance, the components that must remain intact for proper functioning of the catalytic converters were not working in the buses that were surveyed. Air fuel ratio and carburettors were also found to have been tampered with. In some cases, the catalytic converters were even taken out.

The CSE has said all the buses need to adhere to strict maintenance schedule that requires a strong oversight programme. Annual inspection and fitness programme of these vehicles must be supported by the roadside and on-site inspection at regular intervals. Vehicle inspection programme would have to be strengthened to stop tampering and cheating that is rampant under manual inspection regime.

The CSE had made a presentation to the Chief Minister, Sheila Dikshit, and officials of the Transport and Environment Departments recently. Ms. Dikshit had applauded the work done by the CSE and assured that second generation reforms on the pollution front would be unleashed very soon.

The CSE, during its presentation, had further pointed out that in-use emissions tests for CNG buses were inadequate. Under this, only carbon dioxide emissions were monitored.

It said that tampering with air fuel ratio helps lower carbon monoxide and hydro carbon emissions to pass the test will increase the nitrogen oxide emissions from these buses. Since nitrogen oxide is not measured, this increase would go undetected.

Nitrogen oxide emissions would also increase if catalytic converters do not work. Therefore, measurement of nitrogen oxide is important and must be introduced on a priority basis. In view of the fact that Delhi Government is in the process of setting up fully automated centralised vehicle inspection centres for commercial vehicles, nitrogen oxide emission measurements must be introduced in these centres to control any downside of the CNG programme.

The presentation said proper functioning of catalytic converters was essential to check deterioration in emissions from CNG buses.

Currently, catalytic converters for CNG buses are designed to meet the durability of 80,000 km. The Delhi Government needs to link the replacement of these converters to an effective inspection programme.

If the vehicles fail to meet the emission limits within the specified life of the catalytic converters, then the manufacturers would have to take the responsibility of changing the catalytic converters.

It is therefore important that the manufacturers be asked to increase the durability of these converters from 80,000 km to 200,000 km in the new vehicles.

"We are going to seriously look into the submissions made by CSE and ensure that the fight against pollution gets a new direction. Already, steps have been initiated to put in place private competition in various spheres including vehicle inspection in order to wake the Transport Department up from its deep slumber,'' Ms. Dikshit stated.

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