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Pollution: Beeps and bottlenecks


Everyone living in Karachi is familiar with the problems one has to face while commuting, especially during rush hour, when traffic jams are a norm. Being stuck in a traffic jam is not only a waste of time but increases stress and exposes one to air pollution. A number of measures have been suggested to ease the traffic mess on the city’s roads, like signal-free corridors, flyovers and underpasses, etc.

Last year at a seminar held in Karachi, representatives of the Japanese International Cooperation Agency (JICA) suggested the need for a high-quality bus-based transit system for Karachi to meet its transportation requirements; the suggestion was based on their two-year study of Karachi’s transportation system. Bus Rapid Transit (BRT) is an effective transportation system for reducing traffic congestion. It is used in many cities around the world, such as Bangkok and Delhi.

Karachi must opt for BRT as suggested by the JICA. But since that would take a long time to complete, some interim measures are suggested to ease traffic congestion in Karachi; these are also aimed at automotive air pollution control.

In Karachi, the major factors which contribute to traffic congestion include roadside parking (even double parking), absence of proper road marking which prompts people to switch lanes aimlessly, plying of heavy duty vehicles during peak hours, buses and minibuses stopping in the middle of the road and at the intersections to pick and drop passengers, long pick and drop time of buses and minibuses blocking the flow of traffic, misuse of footpaths by shopkeepers that force pedestrians to walk on the road, jaywalking, use of right hand side lanes by vehicles maintaining relatively low speed, absence of car pooling, and non-synchronisation of traffic signals especially the ones that don’t efficiently respond to the volume of traffic flow. Added to this is the abnormal increase in the number of cars, due to the absence of a decent mass transport system.

Bangkok, which can be compared to Karachi, in terms of volume of traffic, has been fairly successful in solving traffic congestion problem. This is mainly due to adequate bus system and sky trains. Traffic laws are less violated, drivers are disciplined and people do not unnecessarily switch lanes. Besides, the officials of the Bangkok transport department frequently undergo training programmes in the transportation engineering division of the Asian Institute of Technology.

A visit to the Saddar area in the evening reveals the extent of automotive air pollution. The key aspect of vehicle emissions control is proper engine tuning and maintenance. Experience shows that qualified mechanics and workshops for this purpose are limited in number and expensive, while the cheaper ones carry out improper tuning, due to which people avoid getting their vehicles tuned, which, in turn, contributes significantly to air pollution. Establishment of government-controlled, low-cost workshops, run by qualified mechanics, backed by appropriate strategy, would get a highly encouraging response from vehicle owners.

A menace, which contributes to auto-related air pollution, is the availability of adulterated fuel; this needs to be checked. Another important factor, not known to many people, is the corrosion of underground fuel tanks at some petrol pumps. This leads to two-fold problems: presence of fine metal particles in the fuel and mixing of water with petrol.

The exhaust pipe of buses, minibuses, trucks and other heavy-duty vehicles should be at the rear end of the vehicle. At present most of the buses in Karachi have their exhaust pipes on the side of the bus, which pumps emissions directly into the adjacent vehicles. Further, the exhaust pipe should extend (from the rear) to the top of the bus. The vertical protruding pipe will discharge smoke upwards. Research has shown that it profoundly helps in efficient diffusion and dispersion of emissions into the atmosphere. The suggested system is all the more important in case of Karachi, as high-rise buildings on both sides of the roads create a vortex effect, due to which air pollutants remain in suspension for a relatively long time. The vertically extended protruding pipe system applies only on heavy commercial vehicles.

The main target of control measures is to reduce emissions per kilometre driven and, control of vehicle-kilometres travelled. Vehicles should be fitted with the “three-way catalytic converters”. Catalytic converters reduce the emissions of nitrogen oxide, carbon monoxide and hydrocarbon. They are however, damaged by leaded fuel. Exhaust Gas Recirculation is also a device for reducing nitrogen oxide emissions.

While it is commonly said in Karachi that the petrol sold is lead-free, some reports suggest otherwise. Lead is mixed with petrol to increase its octane rating; this practice should be stopped. The use of leaded fuel is one of the major reasons of presence of lead in the atmosphere. A study showed that, most of the schoolchildren of Saddar, Preedy Street and Empress Market areas have high blood lead levels.

As far as possible, streets should have one-way traffic system. This will reduce road vehicle density (number of vehicles per kilometre) and will increase the average vehicle speed. This, in turn, will significantly reduce traffic congestion. The lower the vehicle density and higher the average vehicle speed, the lower will be the emissions per kilometre length of the road.

All traffic signals should be properly synchronised; it will reduce traffic jams and prevent idle engine running, which, in turn, will reduce emissions. At present, in most cases, one has to stop at every traffic signal, as the traffic signals are not synchronised.

On-street parking should be prevented as it reduces road width. Major cause of traffic jams is the narrowing of roads due to obstructive parking. Staggered working hours system be introduced especially in main commercial areas to lessen the traffic peaks.

During peak hours, heavy traffic should not be allowed on busy roads. Concept of ‘no-drive days’ should be introduced; for example, no cars should be allowed in Saddar area one day a week. Pedestrian zones should be introduced, for example, around Empress Market. Use of bicycles should be encouraged. In fact, a number of countries are adopting traffic congestion reduction strategy, with use of bicycles as a major option.

There is a need to have an efficient mass-transit system. The major advantage of the mass-transit system is that people would use the mass-transit system instead of their personal cars. A study showed that during peak hours on M.A. Jinnah Road, cars, which carry only 10pc of the load, occupy 75pc of the road space, while buses, which occupy only 25pc of the road space, carry 75pc of the passenger load. This clearly and unnecessarily contributes to traffic congestion.

As far as possible, car pooling should be encouraged. It will reduce the number of vehicles on the roads. Limitation may be imposed on cars with no passenger during peak hours on busy road. For example, only cars carrying three persons should be allowed on I.I Chundrigar Road, during rush hours. But it is important to determine public acceptability before its implementation.

In Karachi, public-transport vehicles are mostly old. About 10pc of the buses are not road-worthy; it also applies to trucks, taxis, rickshaws, vans and cars. The vehicles are significantly older with negligible scrappage rate. Poorly maintained older vehicles yield more emissions as compared to a well-maintained new vehicle.

While worldwide the number of motor vehicles is growing at the rate of 5pc per year, in Karachi it is growing at the rate of 10pc per year, which is more than the population growth rate of the city (5pc per year). The major cause of rapid increase in the number of private cars in Karachi is the non-availability of decent public transport system, absence of mass transit system and rapid transportation.

Heavy duty trucks also emit nitrogen oxides, because of its minimal control; and carbon dioxide, due to its poor fuel efficiency. There is no known method of reducing carbon dioxide emissions from the combustion of fossil fuel in automobiles, except by improving the efficiency of engines, which should reduce the amount of fossil fuel burnt, and consequently the carbon dioxide emissions.

Reformulation of gasoline and use of other carbon-based fuels be examined. Reformulation include removal of lead (tetra-ethyl lead), or reduction to less than 0.015 grams/litre; reductions in volatile organic compounds and carbon monoxide through addictives that promote complete oxidation of the fuel; reduction of evaporative emissions by removing compounds with low molecular weight from the fuel; sulphur is removed by hydrogenation and the proportion of heavier compounds is reduced by hydro cracking and thermal cracking. Emissions from the use of diesel fuel can be reduced by removing sulphur and, by reducing the density of the fuel.

Reduction in traffic congestion is technically possible, provided the problem is handled by qualified people educated in transportation engineering. It is again emphasised here that transportation engineering is a specialised field. Many new concepts have been introduced for reducing traffic congestion and automotive air pollution, which are not known to non-technical people. Honest police officers need to be posted, who should assess and deal with traffic violation effectively. It must be realised that a combination of the highlighted actions would significantly reduce traffic congestion and automotive air pollution in the city.