The city’s coastline is a blessing — not only does the the sea breeze disperse the heat, it also carries away pollutants. But the day is not far when Chennai will overtake Delhi in pollution levels, warns a study of 14 cities by the Centre for Science and Environment (CSE).
Among six mega cities and eight metropolitan cities where the study was conducted, Chennai was found to have the highest average trip length of cars, which means that people who travelled by cars covered longer distances.
When people travel by car, it is usually in ones and twos and when compared to a bus that can transport a number of people, a car, however fuel efficient it may be, becomes a gas guzzler and polluter. So is the case with two-wheelers.
Personal vehicles dominate in terms of daily distance travelled in Chennai and other cities. In Chennai, where the absolute number of registered vehicles is already large, the average annual growth rate of vehicles between 2006 and 2016 was a whopping 12.8%.
With all these vehicles on the roads, Chennai’s PM10 (dust particles below 10 microns in size) concentration is way above the permissible level of 60 micrograms/cubic metre.
Every time we make a trip by personal transport, we contribute two to five times more emissions as opposed to making a trip by public transport. Pollution load per travel trip per year from personal vehicles is significantly higher than that of public transport trips across cities. Though nitrogen oxide levels have seen a spike, they remain within permissible limits. The danger with increasing nitrogen oxide levels is that the cumulative effect of NOx for all travel trips is enormous. This underscores individual responsibility.
It also indicates that in cities with a rising volume of travel, if personal vehicle trips are substituted with public transport trips, transport-related emissions and energy consumption can decline substantially.
With its higher trip rate, trip lengths and low modal share of public transport, Chennai’s emissions per trip are higher than Delhi. What this means, as the population increases in Chennai and it spreads further, is that levels of air pollution, carbon emissions and energy consumption will get far worse, leaving even Delhi behind, the report said.
The only reason why total emissions in Chennai are lower than Delhi is due to its comparatively lower population, which results in comparatively lower overall number of trips and, therefore, fewer kilometres travelled by vehicles, it added.
The report called for time-bound targets to be set for improving the modal share of public transport; walking and cycling; integration of urban planning with transportation planning and adoption of transit-oriented planning to reduce distances.
It also suugested restraints on personal vehicle usage through a stiff parking policy; a low-emission zone approach; tax measures and congestion pricing, among others.
