Tuesday, September 11, 2007

Rickshaws and Vehicular Pollution

Part 3 of a six part series on Pune city pollution and environment. Updated every Tuesday.

Didn't you see my right foot?! In the middle of an argument over a minor accident the rickshaw driver claimed he had poked his right foot out to indicate that he was turning right. Pune has around 60-70 thousand three wheeler rickshaws. They are no doubt a very convenient form of taxi service. To many harried customers, rickshaw drivers are rude and indisciplined, but I don't really find their behavior on the road to be any different than that of private vehicle owners. This is a country where everyone owns a piece of the road, so rules be damned.

But rickshaws do pollute a lot. Below table shows pollution amounts in tons/year for different pollutants for a total of 62, 600 rickshaws, compared with other vehicle types. Source: Emission factors from S. Guttikunda, World Bank. Rickshaw numbers from N. Iyer, Consultant Bajaj Auto. Values represent combined sum for two stroke and four stroke rickshaws. Other vehicle numbers, from Pune Municipal Corporation, Env. Status report 2005.

As I showed in my previous post, buses pollute more on an absolute basis but are more fuel efficient on a per passenger km basis. What about rickshaws? Below graph shows per passenger km pollution for a trip of 100 kms. It shows that rickshaws pollute more than buses and two wheelers on a per passenger km basis.

Source: Emission factors for CO2, PM10 and SOx from World Bank: A Simple Model for Better Air Quality (2005); N.Harshadeep and S. Guttikunda. Emission factors for rickshaw, S. Guttikunda and N. Iyer.
Assumed Occupancy: 2 wheels-1, Car-2, Bus- 40, rickshaw - 2.

To tackle rickshaw pollution, the Road Transport Authority has made a policy decision to convert existing 2 stroke and 4 stroke petrol rickshaws to natural gas powered vehicles. How much reductions in emissions will be achieved by conversion of petrol rickshaws to CNG? (compressed natural gas). Below table shows reduction in emissions in tons/year for rickshaw and for comparison reduction in emission for PMT buses.

Blank fields indicate lack of data for emission factors. However, SOx emissions are expected to decrease by large amounts for CNG rickshaws.

A conversion of existing fleet of 2 stroke and 4 stroke rickshaws to CNG has the potential to reduce CO and HC emissions by around 95 percent and PM emissions by around 40 percent! There would be significant reduction in CO2 (by about 30,000 ton/yr, or about 20%). Public transport contributes to a substantial portion of total vehicular pollution. My admittedly rough estimates suggest that public transport including rickshaw, PMT buses and private company buses (about 8000 of them according to the municipal corporation) contribute about 40% of total SOx emissions, 30% of PM10 emissions and about 35% of CO2 emissions. Conversion to cleaner fuels will definitely lead to improvements in air quality, especially if the several thousand private company buses are also included. But changing fuel quality of public transport alone may not help in the long run. In Delhi, after significant improvements in air quality due to conversion of public transport to CNG, the latest news is that pollution is on the rise again, due to a heavy influx of private vehicles, many of them running on diesel. Pune faces similar problems with about 6000 new vehicles being registered every month. And with the eminent arrival of the much touted 1 lakh rupee car in the next few years, gains in reducing emissions by cleaner fuels in public transport vehicles may be swamped by the enormous increase in private vehicles. A more comprehensive public transport system needs to be pursued with urgency combined with pricing initiatives to make driving private vehicles more expensive.

Finally some thoughts on six seater rickshaws, those horrendous contraptions, which were banished to the outskirts of the city, because they were thought to be "polluting more". Image shows a six seater in Pune suburbs.

I have to admit I have a liking for these beasts. There is no doubt that they offered frequent and cheap transport services, something that the bus transport has failed to offer. In principle they should not pollute more than rickshaws, maybe even less on a per passenger basis, since on average they carry more passengers. But a widespread use of adulterated fuel and very poor engine maintenance has lead to additional pollution. Here's a thought. Why doesn't the PMT offer their own six seater service? Is it necessary that they offer only a bus service? This way at least the fuel quality can be regulated, and drivers can be trained to obey at least a few rules.

But that would mean thinking out of the box!

Part 1. Idling and Pollution
Part 2. PMT buses and Pollution


  1. hey suvrat, i seem to like the 6 seater beasts better than the autos aswell.i really think the pmt ought to take charge of these guys and teach them to abide by the rules and take care of their passengers who seem to be hanging on to their dear lives. i will watch out for more stuff, keep writing, ketaki.

  2. Hi Suvrat,
    I was quite surprised to read that Rick with CNG will still continue to generate PM emissions. Where does this PM come from? I thought CNG is Methane gas and no PM should be generated after combustion. BTW, I observe that Ricks running LPG in Pune indeed generate a lot of smoke. I wonder how this happens. As we all know, LPG and CNG are clean buring fuels. I entirely agree with you regarding public transport improvements.

  3. Dear Suvrat,

    I was wondering, do you maybe know how many 2- and 4-stroke rickshaws are on the road nowadays in India? I hope you can help me. I expect that there are approximately 5 million in total.

  4. Good one sir. The problem is with the investments and the fee to operate a legal rick. http://iforeye.blogspot.com/2010/06/why-six-sitters-are-more-polluting-than.html