The Filthy Delhi Air: How to Control Vehicular Pollution?

While adopting advanced emission standards is important, one should not lose sight of the low hanging fruits that can help improve the quality of air.

In November last year, environmentalist Sunita Narain and senior advocate Harish Salve alerted the Supreme Court of India to the dangerous level of cancer causing Particulate Matter (PM) 2.5 in Delhi’s air. As if statistics were not enough, in theatrics of sorts, they pulled out a PM measuring machine and informed the judges that PM 2.5 levels were four times the safe limit inside the courtroom. Alarmed at city’s inhabitants breathing polluted air, the court asked the government to file a response to the documents filed by Mr. Salve.

Delhi has an arduous history of battling pollution, and surprisingly it is not the executive or the legislature but the judiciary that has stepped in to fight against air pollution in Delhi. Almost 15 years ago, Delhi switched its public buses from Diesel to much more innocuous Compressed Natural Gas (CNG) following a Supreme Court order. The replacement of entire fleet of diesel run public transport with one fueled by CNG was immensely successful in bringing down pollution levels in the capital.

        Levels (annual average) of Critical Air Pollutants in Delhi over the past 23 years

However, after almost a decade of breathing relatively clean air, Delhi has lost the battle against air pollution, becoming the most polluted city in the world as per the findings of a World Health Organization (WHO) study. The improvement in air quality achieved because of cleaner CNG based public transport has been nullified due to the sheer number of vehicles on the road. Today, Delhi has more cars than Mumbai, Bangalore and Chennai combined and is adding 1400 new cars to the roads each day. Given the heavy diesel subsidy (withdrawn only in 2015), almost half the cars in the city today run on Diesel - a declared carcinogen - as compared to the year 2000 when only 4 percent used Diesel. In this situation, it is not surprising to learn – courtesy a study done at Jawaharlal Nehru University – that 62 percent of all fine particles are contributed by the transport sector.

Particulate matter present in the air is a threat to human health. Owing to their small size these particles enter the bloodstream by penetrating the lungs, causing cardio-respiratory problems. To this end, the report on Global Burden of Disease puts air pollution as the fifth largest killer in India, causing a loss of $18 billion due to shortened lifetimes and inflated medical expenses.

Despite damning statistics, governments have been tardy. Stirred by the poor air quality and government apathy towards environment, advocacy groups have been vociferously demanding quicker implementation of Euro IV norms in 2015-2020 against the 2017-2025 deadline proposed by the Auto Fuel Vision and Policy. At present the pollution norms in India are 10 years behind those in Europe and the demand to align the Indian Bharat Stage (BS) norms with the Euro norms is justified and in the right direction but suffers from some practical constraints in areas of fuel refining and engine technology.

Any vehicle emission reduction program has two essential goals; a decrease in overall vehicle emissions and the elimination of harmful by-products of combustion like NOx, CO, PM et cetera. The former can be achieved by improving the fuel efficiency of the vehicle. During the decade between the year 2000 and 2010, India witnessed an annualized 1.3 percent improvement in fuel efficiency to 16.5km/L. However, to achieve the target of 21km/L by 2021-22, an annualized 3 percent improvement is required. This requirement necessitates the use of a lean Air-Fuel combustion mixture (more air, less fuel) in the engines. Though it may sound counterintuitive, a mixture of more air and less fuel when burnt produces a higher temperature inside the engine, on account of complete combustion of the fuel. A higher combustion temperature in turn breaks down nitrogen (N2) present in air to form harmful nitrous oxides (NOx). The NOx so formed can be treated using exhaust aftertreatment devices but these devices are damaged by the high sulfur content of the fuel used in India (BS III Sulfur content – 350 ppm).

Thus any reduction in vehicle emissions requires a fuel with low sulfur content (10-50ppm) and lean burn engines with exhaust aftertreatment device. Both require large amounts of capital investment in refining infrastructure and product development, leading to cost escalation in price of fuel and vehicles for the consumer. Therefore, any up gradation of emission regulation can only be incremental, given the extreme price sensitivity of the consumer in a developing economy like India.

In face of the National Green Tribunal order banning diesel vehicles over 10 years of age, the government will be forced to look towards near term solutions that can arrest further deterioration of air quality. If such measures are not taken, then it will be long time before Delhi could breathe clean air. The NGT order though in right spirit, would not only cause financial hardship to vehicle owners but will also be ineffective in reducing pollution. A study at IIT Delhi highlights that these old vehicles are not a major source of air pollution in the city. The report argues that only 7% of the vehicles on the roads are over 10 years old and a ban on these vehicles will reduce PM 2.5 levels by only 1%. A more pragmatic approach would be to make a fitness test for vehicles over 10 years of age mandatory. This way, vehicles exceeding the emission limits will be de-registered and pulled off roads instead of a blanket ban.

Other measures, aimed at reducing total number of vehicles on the road include strengthening public transport systems like metro, bus services and ensuring last mile connectivity for users of Metro etc. Singapore has been extremely successful in building a strong urban transport network thereby limiting the number of vehicles on roads. Easy availability of taxis discourages ownership of private vehicles. The proliferation of mobile taxi services like Uber, Ola Cabs etc gives us the opportunity to take many private vehicles off the roads and reduce traffic jams, pollution and parking woes of the city. However, the same taxi services can also discourage people from using mass-transit options like bus and metro. A deeper study is awaited to ascertain the environmental impact of the new taxi services on urban roads.

Massive traffic jams are a problem for all major cities in the world, a paper published by researchers at Harvard School of Public Health estimates that by 2030, the economic cost on account of fuel wastage due to road congestion would be around $100 billion in the 83 cities that were part of the study and $17 billion would be spent as healthcare expenses in these cities by the same year. In a smart measure, Paris recently adopted road rationing by allowing vehicles with even and odd registration plates to drive on different days. Such measures have been adopted in other high pollution cities like Beijing as well, and have been successful in reducing traffic snarls and air pollution levels.

Delhi being a commercial hub in North India, attracts large number of commercial vehicles, these trucks entering the city are a major source of diesel pollutant, given that most of these vehicles are BS III compliant and do not follow the latest BS IV norms on account of their registration with transport authorities outside Delhi. The movement of BS III trucks through the city should be limited and they be charged a pollution tax on entering city limits. This cess could be used to fund clean environment initiatives.

Finally, from the aspect of sustainable mobility, it is important to promote electric and hybrid vehicles. Delhi has a significant number of e-rickshaws but government should also encourage electric cars by way of low interest loans or reduction in road tax for such vehicles. This will go a long way in curbing urban pollution.

While long term measures like advanced emission standards will still take many years to kick in, it is important that we capture the low hanging fruit by ensuring better traffic management, improved public transport services and alternate energy vehicles, if we are to effectively control air pollution.

This post was originally published on 31st May 2015 at policywonks.in