EFFECT OF ODD EVEN SCHEME TO COMBAT AIR POLLUTION IN NCT OF DELHI

Aparna Katiyar 1 , S. K. Singh 2 and A. K. Haritash 3 . 1. Post Graduate Student, Department of Environmental Engineering, Delhi Technological University, Bawana Road, Delhi, India. 2. Professor & Dean, Department of Environmental Engineering, Delhi Technological University Bawana Road, Delhi, India. 3. Assistant Professor, Department of Environmental Engineering, Delhi Technological University, Bawana Road, Delhi, India. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History

permanent. Similar road-rationing rules are imposed in many places around the world like Paris, Mexico and Bogota to curb road jams and pollution. The scheme has been performed in two phases. One from 1st to 15th January, 2016 and the second phase of the scheme was implemented between 15 th to 30 th April 2016 with the objective of reducing air pollution in Delhi. The odd-even scheme applied to four wheeler Passenger/Private Cars. The AAP cabinet announced private vehicles to run across the city based on their registration numbers. If a vehicle's registration number ends with an odd digit, it will be allowed on the road on January 1 that is on odd numbered days, while that ending with an even number can be driven on the second, and so on. This step has been taken as a measure to bring down and control air pollution. Air-pollution levels in Delhi rose 15% during the 15-day period (January 1 to 15, 2016) of the state government"s odd-even measure over the previous 15 days (December 17 to 31,2015), according to an analysis of PM 2.5 (particulate matter)data, generated by various studies.

Odd Even Scheme:-
The odd even scheme is one of the road rationing system also called as alternate-day travel is a travel demand management strategy aimed at reducing the negative obverse generated by urban air pollution or peak urban travel demand through artificially restricting demand (vehicle travel), especially during the peak periods or during peak pollution events. This objective is achieved by restricting traffic access into an urban area, city or district based upon the last digits of the license number on pre-established days and during certain periods, usually, the peak hours.
Delhi Government had imposed this scheme in two phases. Initially the scheme was implemented from 1 st January 2016 to 15 th January 2016 and the second phase had been in operation from 15 th April to 30 th April 2016. According to the notification issued by the government, from 8 am to 8 pm private vehicles with odd registration numbers will be allowed on the road on Mondays, Wednesdays and Fridays. Vehicles with even numbers will run on Tuesday, Thursday and Saturday. But on Sundays there was no as such restrictions.
This rule will not be applicable on emergency vehicles like PCR vans, fire tenders and ambulances, and on public transports like CNG-driven buses, taxis and auto-rickshaws.
The government also decided to exempt two-wheelers from this rule. This system, therefore, was applicable only on private-owned four wheelers running across Delhi, and on those coming in from other states. And that includes vehicles used by ministers and bureaucrats of all ranks.
To make the scheme work effectively the government has added the public transport will be strengthened from the first of January. This will include increasing the frequency of metro trains across the city.

Analysis of data:-
The air quality in Delhi is monitored through a set of Continuous Ambient Air Quality Monitoring System (CAAQMS) and manual stations (NAMP). The present analysis is based on the data collected by CPCB from 08 operational CAQMSs including 04 of its own (Shadipur, Dwarka, Dilshad Garden & Parivesh Bhawan) and 04 belonging to DPCC (Mandir Masg, R. K. Puram, Punjabi Bagh & Anand Vihar). Apart from this, data has also been collected from 07 manual stations of CPCB (Pitampura, Sirifort, Janakpuri, Nizamuddin, Shahzada Bagh, Shahdara & BSZ Marg) which operate on alternate days. The overall contribution of vehicular pollution in ambient air in Delhi during winter season is estimated to be around 20-25% in respect of PM 10 and PM 2.5 . However, in terms of emission load, it contributes about 9% and 20% respectively for PM 10 and PM 2.5 , as per IIT Kanpur study, of which the 4-wheeler passenger cars contribute about 10%. The odd-even scheme could have theoretically contributed to PM reductions in respect of exhaust emissions from off-road odd or even cars, marginal reduction in road dust and secondary pollutants.
The data analyses for days preceding (period from 25th to 31st December,2015) and post (period from 16th to 21st January, 2016) to the odd-even scheme, shows that during pre-odd-even scheme December 25-31, 2015; the pollutants viz., PM 10  Overall, it can be stated that while some reduction in air pollution is likely to happen due to odd-even scheme, a single factor or action cannot substantially reduce air pollution levels in Delhi. Therefore, a comprehensive set of actions following an integrated approach is required to make substantial improvement in air quality.

Another analysis done by System of Air Quality and Whether Forecasting and Research (SAFAR) also showed a similar trend in air quality status of Delhi.
The pollutants for which data have been considered for the above said assessment include PM 10 , PM 2.5 , SO 2 , Benzene, O 3 ,NO 2 and CO of which ozone, PM 10 and PM 2.5 is the major one.It also monitored the finer PM 1 particles, or particles of size less than 1 micron, which are known to penetrate deep into the lung tissues and the cardiovascular tract.

Ozone:
The levels of ozone, which scientists describe as the most critical summer pollutant in Delhi, between April 15 and 30, peaked at 88 parts per billion or 176 micrograms per cubic metre (µg/m³) on April 30, the last day of the oddeven scheme, according to SAFAR data. In comparison, during April 1-15, the levels peaked at around 60 parts per billion or 120 µg/m³ on April 6.
On April 24, ozone levels hit 75 parts per billion or 150 µg/m³, the first sharp rise seen during the scheme, from around 62 parts per billion or 124 µg/m³ the preceding day. Between April 19-22 ozone levels remained around 51-52 parts per billion or 102-104 µg/m³. According to scientists, the level of the pollutant spiked consistently between April 17 and 19, ranging between 75 and 80 µg/m³. An initial dip was reported between April 15-17.
Comparing this with data from April last year, the trends are quite similar, according to scientists. On April 24 last year, ozone levels had peaked at 90 parts per billion or 180 µg/m³, the highest between April 15-30. Between April 1-15 last year, a peak of around 70 parts per billion or 140 µg/m³ was observed in ozone levels on April 5, the highest during the first fortnight of the month. This year, the peak was observed on April 6.

PM 1
Between April 15-30, the data shows, PM 1 levels peaked on April 30 at around 78 µg/m³. After recording less than 60 µg/m³, till April 23 which is the safe limit for the larger PM 2.5 particles , the PM 1 levels escalated between April 25-28 at around 75 µg/m³. After dropping to 60 µg/m³ again on April 29, the levels shot up on the last day of the scheme. "The safe limits for PM 1 are not defined as yet in India. But considering that these are finer than PM 2.5 and they can penetrate deeper into the respiratory and cardiac organs, the safe limits should be far lower," a studied. In comparison, between April 1-15, PM 1 levels peaked at around 70 µg/m³ on April 3. Three peaks of around 60 µg/m³ each were observed on April 4, 7 and 9, before the levels dropped to between 30 and 40 µg/m³ till April 14. On April 15, levels again hit 60 µg/m³. PM 1 levels were not being monitored last year.

Conclusions:-
The Government of NCT of Delhi has implemented Odd Even Scheme with aim to reduce air pollution level in the city. Data from either the DPCC or the CPCB has not shown any improvement in air quality. Similar trends can be observed from data from the Indian Institute of Tropical Meteorology"s SAFAR, which showed that the quality of air continuously deteriorated from December 25, with pollution levels being "severe" on four out of the first eight days of January, worse than the previous week. It is concluded that the scheme did not worsen air quality; meteorological conditions did, but the scheme was not able to mitigate this impact. For one, wind, which disperses pollutants, has fallen consistently in speed since December. On the other hand, higher temperatures in this year as compared to the same time last year, usually improve air quality by dispersing pollutants in the atmosphere, but the concentration level of particulate matter in January 2016 is twice as much as it was during January 2015. It is quite clear from data about sources of air pollution in Delhi that cars are not the major polluters. The draft report of the Indian Institute of Technology, Kanpur, which was commissioned by the Delhi Government in 2013, on the sources of particulate matter found that vehicles contribute to 20 percent of PM 2.5 concentration. Among them, trucks and two-wheelers together contribute to 80% of pollution and cars contribute 10% only. This means that the contribution of four-wheelers to air pollution in Delhi is just 2%. On a given day, when half the cars are taken off the road during the odd-even trail, with additional exemptions, only a 0.5-1% reduction in pollution can be expected. This could be marginally higher depending on the impact of the wind.
In Delhi, the transport, industrial and the domestic sectors were also considered as the major contributors towards the rising ambient air pollution levels, in addition to the presence of natural dust due to meteorological conditions. Besides anthropogenic sources, some other factors that contribute in the buildup of pollution levels are climate and natural sources. Delhi has a semi-arid climate, with an extremely hot summer, average rainfall and very cold winters. Mean monthly temperatures range from 14.3 °C in January (minimum 3 °C) to 34.5 °C in June (maximum 47 °C). Dust storms occur frequently during summer months leading to build-up of particulate matter in the atmosphere. It is concluded that two-wheelers along with many other environmental factors are responsible for more PM 10 and PM 2.5 than cars when it comes to polluting the air.