All passenger cars sold in the metropolitan cities of Delhi, Bombay, Calcutta and Madras have to be fitted with catalytic converters.

The major pollutants from petrol driven vehicles are carbonmonoxide(CO), hydrocarbons(HC) and oxides of nitrogen(NOx).

CO affects cardiac and pulmonary functions, apart from the central nervous system, due to high affinity with haemoglobin.
HC irritates eyes and throat and are carcinogenic
NOx causes respiratory disorders and adverse changes in the cell structure of the lung wall.

Toxic substances in the exhaust gases can be rendered harmless by catalytic treatment.

The catalytic converter is a device installed between the exhaust manifold and muffler in an exhaust system that converts pollutants to harmless by-products through a catalytic chemical reaction.

Tentative limits have also been announced for cars for the year 2000/2001. All cars have to achieve CO 2.72 g/km and HC + NOx 0.97 g/km. The emission measurement from that year will be on a cold start engine whereas now it is made on a warmed up engine.

Every year, Mumbaiites lose 20.2 million work days due to pollution-related illnesses

9.01 lakh people suffer from pollution-related asthma

5,800 people are admitted to hospitals for pollution-related respiratory symptoms

24,000 adults and 2.20 lakh children are affected by chronic bronchitis caused by pollution

87,000 visits to emergency rooms are due to pollution-related helth problems

Rs.48,633.12 million is spent in health-damage costs

The central government aims to phase out leaded petrol by the year 2000, as better quality fuels would reduce vehicular pollution substantially.

Most petrol pumps in and around Mumbai supply only unleaded fuel and this shall soon be extended throughout the country.

In 1975 Mumbai had a total vehicle population of around 2.35 lakhs. Today, the city roads are trafficked by roughly 11 lakh vehicles - all these vehicles belching a toxic cocktail of noxious gases like carbon monoxide, sulphur dioxide, oxides of nitrogen, hydrocarbons and other particulate matter.

Vehicles contribute to a shocking 52% of the total air pollution in Mumbai. (vehicle population in Delhi is thrice that of Mumbai and vehicular pollution contributes to 67% of the total air pollution)

A World Bank study reports that 40,000 premature deaths, 17 million respiratory hospital admissions occur in India due to air pollution.

The inability of the government to address the crucial issue of air quality management, despite of having a plethora of Laws and Acts on pollution control has resulted in the dramatic increase in air pollution in most Indian metropolises.

Two-wheelers account for a major part of vehicular pollution in urban cities.

Due to the inherent drawbacks in the design of 2  - stroke engines, these vehicles discharge about 20-40% of the fuel un-burnt/partially burnt.

Two -wheelers account for the emission of more than half of the hydrocarbons and of the carbon monoxide of all other vehicles put together.

The 2-stroke engine, in spite of R&D efforts towards improving its design, will continue to be a high emitter of hydrocarbons and carbon monoxide.

Most of the three-wheelers in urban cities are petrol-driven, powered by 2-stroke engines. These vehicles are also high emitters of carbon monoxide and hydrocarbons. In addition, it is widely believed that petrol is adulterated with kerosene, which results in emissions of thick black smoke.

Overloading is a major cause for pollution, as most of these vehicles continue to function beyond the recommended age and carry more than the permitted load of passengers.

All buses, particularly during peak hours, carry more than the recommended load of passengers. This results in higher smoke emissions.

The diesel trucks, similar to buses, emit high levels of smoke and particulate matter. Most of these vehicles are very poorly maintained.

The Petroleum Industry has not made necessary investments to improve refining technology. Standards for fuel with respect to environmental parameters -- lower benzene and sulphur levels, will come into effect only in the year 2000. Industry meanwhile is resorting to devious ways to maximise subsidised diesel production by taking "wider-cut" (extracting heavier fraction of the distillates) and through secondary distillation process (cracking bottom of the line distillates), which lead to high level of carbon and sulphur in the fuel.

Refining technology is obsolete and ill suited to process the high-sulphur crude purchased cheap in the international market.


Should we continue breathing poisoned air, largely because of the government's inability to balance environment and development?
Fresh Air?!?

The government definitely has drawn up tighter plans for the future. The infrastructure plans of the state government and the central government shall soon bring some most needed fresh air.

Most of the newer cars being manufactured in India are using upgraded technology and are lesser polluting.

Catalytic Converters are necessary as they convert hydrocarbons and carbon monoxide to carbon dioxide and water.

Cars with Catalytic Converters use unleaded fuel.

A catalytic converter requires unleaded petrol, because lead poisons catalyst, making it ineffective.


Unleaded fuel can also be used in older cars without catalytic converter.

Unleaded petrol of adequate octane quality (87 RON) can be used in any vehicle, old or new, with or without catalytic converter.
Presence or absence of lead alone does not effect knocking in the vehicle, it is octane number of fuel, which affects knocking. If octane number of unleaded petrol is same or higher, there is no question of knocking.