What Is Cng?

Introduction of CNG (Compressed Natural Gas) in New Delhi and its impact on the environment

By : Arjun Gulati

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Introduction

What is CNG?

CNG — compressed natural gas, a fossil fuel that’s one of the cleanest-burning alternative vehicle fuels. (http://autos.yahoo.com/green_center-article_40/). CNG is a cheaper mode of transportation than Diesel and even gives a higher average on the car. An alternative fuel for motor vehicles; considered one of cleanest because of low hydrocarbon emissions and its vapors are relatively non-ozone (www.nsc.org/EHC/glossary.htm)

Air pollution is becoming a cause of concern in major cities and large urban areas throughout the globe. The major contributor towards air pollution is vehicular pollution. It is well known that air pollution attributed to road traffic varies because of different factors such as fuel used, engine technology, driving condition, emission control devices and meteorological conditions. The major contributor for the pollution emission is the type of fuel used as it impacts the remaining factors mostly. CNG was introduced as an alternative fuel in New Delhi as in the late Nineties as it was voted as one of the most polluted cities in Asia, with vehicles accounting for 70% of the pollution emissions and the pollution levels exceeded World Health Organization standards by nearly five times. (http://cities.expressindia.com/fullstory.php?newsid=85665). The capitals sky was covered with black smog, children were being born asthmatic, respiratory problems spread around the capital and cancers menaced the city. The SPM levels in Delhi in 1998 were recorded 7.6% times the permissible level at certain days.

Hence severe steps were needed to control the level of pollution in the national capital territory. A bill was passed and the entire public transport system in New Delhi was asked to use Compressed Natural Gas as an alternative fuel. Hence Over 2100 buses, several taxis and many 3 wheel public automotive transport were converted into CNG. After the introduction of CNG as a necessity in the public transport system the government and banks came out with several schemes for the people. Such as no sales tax on conversion of vehicles from diesel to CNG, easy loans from banks for conversion. Now Delhi boasts of Asia’s largest eco friendly bus system. Delhi also banned the use of any of these automotives which were older than fifteen years.CNG was introduced as its emission levels were much less as compared with diesel(Refer to the chart below) and it was a much safer alternative fuel as compared with LPG etc. If there was to be leakage of CNG it would evaporate in the air without causing any grave concern. Before diesel was used as the fuel in the public transportaion system as it was a cheaper fuel costing 60% of petrol. The pollution levels emitted from diesel are quite high. According to an estimate of a World Bank study on Delhi pollution in 1996, diesel vehicles were responsible for as much as 62.5 percent of the total particulate emissions from the transport sector.

Comparative Emissions from CNG & Diesel

Fuel Emissions in gkm-1

CO NOx PM

Low S Diesel (500 ppm) 1.32 14.72 0.22

ULSD(50 ppm) 1.41 14.32 0.16

CNG 0.66 9.87 0.05

1. Source: www.petroleum.nic.in/afp_con.html

There were a number of obstacles before CNG could have been introduced inside Delhi.Like several Myths came up like CNG is not economical viable, CNG buses are unsafe for use,CNG buses emit the same amount of particulate matter as Diesel buses and the list goes on but all these myths were proved wrong by various organizations and it came into implementation.

Of all the interventions made to clean Delhi’s air, conversion of diesel buses to compressed natural gas has been the most important, (according to a recent study by the Washington, DC-based think tank Resources for the Future.)The conversion of buses to CNG was the most important as the buses travel most of the kilometers in the day hence contributing more to the pollution load. Therefore the conversion had led