New Delhi, the Capital city of India and world?s second most populous city with 25 million residents in 2014 had PM 2.5 pollution levels, According to the Ambient Air Pollution (AAP) report for the year 2014, Delhi which is the highest in the world, followed by Beijing. This result was based on the monitoring of PM measurement of outdoor air pollution from almost 1,600 cities in 91 countries.
The highest concentration of PM 2.5 form of air pollution is supposed to be a very serious matter and can lead to respiratory diseases and other health problems like lung cancer.
According to the WHO, air pollution is the fifth largest killer in India.
Carbon monoxide (CO), a dangerous gas emission, is around 6,000 microgram per cubic metre in Delhi, which is much above the the safe level of 2,000 microgram per cubic metre.
The level of nitrogen dioxide (NO2) has also been increasing.
According to the Ministry of Earth Sciences, Delhi?s air quality index (AQI) is 121, which is described as ?poor.? The AQI is an index for reporting daily air quality, about how clean or polluted is the air.
While in recent Mercer?s 2015 annual quality of living survey, New Delhi ranks 154 out of 230 cities due to bad air quality and pollution. The World Health Organisation (WHO) ranks New Delhi as world?s most polluted city.
But the city is rapidly growing and population is increasing day by day. The pressure and rapid growth of the population is deteriorating the environment.
There has been large scale unplanned development of industries and factories in recent times. Studies reveal that only around 20% of the industrial units are set up in approved industrial areas whereas the rest of them are in residential, commercial or environment protected area.
There has been huge rise in pollution from vehicles spite of developing Delhi Metro which leads to traffic congestion and increasing air and noise pollution.
The vehicles counts are so much that Delhi has more of vehicles than India?s other three Metropolitan cities of Kolkata, Chennai and Mumbai together.
There is also significant dispute over the extent of the city's green cover. City authorities claimed in 2008 that the green cover had increased from 26 km² to 300 km² moreover, the Delhi Forest Act stipulated that for every felled tree ten saplings need to be planted. Critics point out that the data as well as the meaning of "green cover" are unclear. The actual increase may be only half of what was claimed, and there are estimates that some 100,000 trees had been cut in Delhi, due in part to the construction of the Metro in Delhi and the Delhi Bus Rapid Transit System.
Out of steps taken by Government are providing ?lung spaces? which is ensured by Delhi Development Authority (DDA), Of the city's 44777 hectares, 8422 hectares are reserved for "the Greens", of which the DDA manages more than 5050 hectares.  There is a policy for afforestation, atmospheric pollution, bio-medical waste, domestic refuse, and water and sewage treatment. Additionally, there are action plans to encourage public participation in environmental problems.
Given the continued growth of the city and its population, problems are tackled only with difficulty—for instance, the Yamuna action plan (YAP) projects spent $500 million between 1993 and 2005, yet the river's pollution actually doubled during this same period.
 
But these steps are like drops in Ocean, couple of days ago, NDMC has came up with a new action plan and made us optimistic about its willingness to curb pollution.
For increasing green cover NDMC (New Delhi Municipal council) has decided to double up the saplings count that was planned to plant in this monsoon season in its control areas.
The NDMC said that about one lakh saplings will now be planted in its area, double than the earlier target of 50,000.
During the first two phases of the drive, which was launched last month, over 46,000 saplings have been planted and today 38,000 saplings were planted. 
   To make the programme a success, the whole NDMC area has been divided into 14 zones and huge manpower has been deployed. A large variety of flora including Molshree, Ficus Bush King, Cycus Palm, Ficus Panda, Chandini, Neem, Jamun, Kusum, Ashok trees and saplings are being planted in different parts of the city.
 Hope this thing do some good of city, which is ailing from disease of pollution.