The National Capital Territory (NCT) of Delhi is an Urban Ecosystem known for two prominent landscape features, River Yamuna and the Delhi Ridge or the Northern extension of Aravalli hills. The NCT of Delhi has a geographic area of 1,483 sq km and is spanned over a greatest length of 51.90 km and a greatest width of 48.48 km.

The population of Delhi according to the Census of India 2011 was 16.3 million. This figure is now projected to have crossed 25 million. Consequently, the NCT of Delhi has very high population density and an ever increasing ecological footprint.

The following article discusses the environmental issues and concerns of Delhi, that have collectively become a key challenge for sustaining the urban growth of Delhi today.

Public Health

One of the biggest threats to public health in Delhi is because of rising air pollution in the city. The Respirable Suspended Particulate Matter (RSPM) values in many parts of Delhi exceed the permissible value in most parts of the city almost throughout the year. In May 2014, the World Health Organisation declared Delhi to have the worst air quality in the world.

It is no wonder then that the Air Quality Index in Delhi averages in the Unhealthy to Very Unhealthy range. Consequently, more and more people are getting unwell due to lung and related infections and children, the elderly and the sick are the worst affected. In December 2015, in what was an unprecedented decision, the Government of NCT of Delhi shut down schools due to air pollution.

The causes of air pollution in Delhi include vehicular exhaust from the large number of vehicles that ply on its roads, construction work, rising population and its demands to stubble burning in the neighbouring agricultural states of Punjab, Haryana and Uttar Pradesh. Another cause that often gets overlooked are the weathering Aravalli hills that are also being destroyed in many parts of Delhi NCR in the name of development.

Water pollution is another hazard to public health. Many households complain of receiving impaired quality water, which is perhaps due to mixing of potable water with sewage water due to break in the pipes. There is also an undocumented dependence on ground water in Delhi, which is concerning since many parts of Delhi are noting heavy metal laden ground water.

High density of population in Delhi also poses threat to public health. Noise pollution on the roads and some localities of Delhi is a common problem. Quality of Life is also significantly under question especially in slums, some urban villages and in the always crowded Delhi Metro, buses and marketplaces. There is also an year-round threat of disasters such as epidemics, fire, etc.


In addition to water pollution, water availability has also become a concerning challenge for the city of Delhi. All the fresh water brought to Delhi by River Yamuna is withdrawn at Wazirabad Barrage and consumed. Very little water flows downstream of this barrage thereby threatening aquatic life. The latter is missing between the Wazirabad and Okhla barrages, where the water quality remains unfit even for industrial use.

Ground water table is also consistently declining in Delhi and there are predictions which suggest that South Delhi part of Delhi will soon become a desert if it does not regulate ground water withdrawal. The floodplain of River Yamuna, which could have stored water, is constantly being consumed and permanent structures are being constructed on it. The large number of wetlands in Delhi are also shrinking and being lost in the name of development.

Management of waste water is also a challenge and most of it flows untreated in to River Yamuna through the Najafgarh drain. The latter is itself a foul smelling sewage canal that flows through a large part of the NCT of Delhi. People have also lost confidence in the water supply of Delhi and it is uncommon to find houses without an R.O. device anymore. All in all, Delhi needs to take proactive steps today so it can secure its water resource for present and future generations.

Urban Biodiversity

Delhi was once the second most bird diverse capital city in the world, after Nairobi. There have been reports of spotting over 450 different bird species in Delhi. However, today this number is constantly shrinking. Loss of wetlands, cutting of trees, construction of more and more buildings are some of the factors that have led to a reduction in bird diversity in Delhi in recent years.

Sparrows, once commonly found in Delhi, have now become so rare that in October 2012 the Government of NCT of Delhi had to declare it the State Bird of Delhi to aid its conservation. Birds are the indicators of the health of the ecosystem they inhabit. The shrinking sparrow population in Delhi was perhaps an indication of the worsening of the air pollution scenario of the city, so much so that in 2015 schools had to be shut to save our children from falling sick.

Other species of animals with whom we share Delhi’s urban ecosystem include Neelgai (blue bull antelope), monkeys, snakes, butterflies, dragonflies, porcupine, civet cats, jackals, etc. Many of these animals are found in the Yamuna floodplain or in the Delhi Ridge. However, developments on the Yamuna floodplain and encroachments in the Ridge have shrunk the habitat of these animals and there numbers are constantly declining.


Delhi generates tonnes and tonnes of municipal solid waste each day. This waste is usually collected from the households and ultimately ends up in one of the three overflowing landfills in Delhi, at Bhalswa, Ghazipur or Okhla. Segregation of waste is still a challenge in Delhi and only very few colonies are institutions are separating their dry waste from wet. Consequently, the landfills are not only overflowing, they are also coming down as landslides and killing people in the process.

The three landfills of Delhi are also an eye sore and add significant suspended particulate matter and other gases in Delhi’s atmosphere. They are certainly a source of greenhouse gases like methane and are therefore also contributing to global warming and climate change. In addition to this, Delhi needs to do much more to handle its electronic waste (ewaste) in a safe and sustainable way. Although banned, burning of waste is also a big problem in Delhi since it also adds to air pollution problem.


The main cause of air pollution in Delhi is the transport sector. There are more cars on the road of Delhi than there are in the other three metropolitan cities of Mumbai, Chennai and Kolkata. The car is the ultimate freedom, and spotting cars with only one person is a common sight in Delhi. With the coming of the Delhi Metro, there was some initial reduction in the number of cars on the Delhi roads.

However, the situation today seems to have returned to what it was in the pre-Metro days. Rush hour traffic jams are normal in Delhi. It is strange to see roads, buses and the Metro all crowded with people at the same time. Clearly, planning in the transport sector needs a shot in the arm. Finding a traffic jam on top of a flyover, especially in South Delhi, is also a common sight. There is need for promoting public transport in Delhi, especially surface transport like buses which need to be made more punctual and comfortable.

Last mile connectivity, a key challenge to the success of Delhi Metro, continue to be a problem. The introduction of innumerable erickshaws and cycle-rickshaws have only crowded the road even more. Moving in Delhi has become increasingly unpredictable as many different types of vehicles continue to compete for the same limited space on the roads of Delhi. The transport sector is one sector which is clearly shouting for an urgent de-congestion of Delhi through suitable development policies.


The per capita household electricity consumption in Delhi is almost double that of the national average. Delhi consumes more electricity than all the other metropolitan cities put together. Despite this, not many measures are being taken to optimize Delhi’s energy demand or regulate it in any way. There is greater awareness needed to promote energy efficiency and also to carry out Energy Audits of buildings and institutions.

What is more concerning is the fact that most of this electricity comes from non-renewable resources which contribute directly to global warming and climate change. There is some awareness in the people on the need to shift to renewable energy, but the transition is too slow to bring any immediate benefits. This is despite the fact that Delhi’s share of renewable energy shot up from 23 MW in 2015-16 to 177 MW in 2018-19.

Food Supply

The large population of Delhi has an even larger ecological footprint. And Delhi receives food supply from almost all parts of the country, and mainly from the neighbouring agrarian states. However, there is an increasing concern of food grains, fruits and vegetable being laden with excessive concentration of chemicals like pesticides and fertilizers. There are reports of how these chemicals could be harmful for the human body.

There is thus an increasing interest in consuming organic food in the people of Delhi. However, the organic supply chain is often short in supply and there is a need for promoting urban farming initiatives in Delhi. This will help in making organic food available and will also reduce our dependence on other states for food thereby reducing Delhi’s ecological footprint.

Environmental Education & Awareness

Preliminary surveys by some agencies indicate a lack of environmental awareness and sensitivity in a large percentage of Delhi’s population. An earlier study by Delhi Greens showed how a large percentage of Delhi’s population are migrants who do not really consider Delhi to be their city. There is thus an urban stakeholder crisis in Delhi which needs to be overcome through spreading environmental education and generating environmental awareness in the masses.

Last updated on 1 May 2019 by Dr. Govind Singh