The national capital has only 7.94 % of its total geographical area covered by trees. This has came down from 8.07 % in 2011.

Out of the total geographical area of 1,483 sq km, only 120 sq km area was covered with trees in 2011, this further decreased to 118 sq km in 2013.

On April 15, Delhi high court appointed amicus curiae Kailash Vasdev informed the court that over one lakh trees were cut during 2006-2010 to make way for Delhi Metro and PWD projects, bringing down the city's green cover to 10% from the minimum desired level of 33%.  This was done without any replanting to make up for the loss of greenery.  He also informed the court that there were 26 notified forests in the city, but very few are left now. Delhi has only 10.2% forest cover left even though Forests Act says 30% is minimum.

The Delhi high court then asked the govt and various departments in Delhi to give the details on how many trees were cut and how many were planted by them.

With its record of more than a lakh trees to have disappeared, Delhi is still in a better position than most of the states. Sikkim for example has only 0.44 % tree cover. Condition is worse in Uttar Pradesh, Haryana, Bihar, Jharkhand, Tamil Nadu with constant decrease in the tree cover.

Here is why one should be worrying about the tree cover in India

(The data in % show tree cover in 2011 and 2013)

State/ Uts	2011	2013
Andhra Pradesh	2.60	2.61
Arunachal Pradesh	0.66	0.79
Assam	1.99	2.02
Bihar	2.52	2.3
Chhattisgarh	2.86	2.56
Delhi	8.07	7.94
Goa	7.73	9.03
Gujarat	4.00	4.26
Haryana	3.15	2.9
Himachal Pradesh	1.12	1.25
Jammu and Kashmir	2.95	3.45
Jharkhand	3.66	3.3
Karnataka	2.99	3.09
Kerala	7.09	8.09
Madhya Pradesh	2.30	2.3
Maharashtra	2.95	2.97
Manipur	0.86	1
Meghalaya	2.58	2.98
Mizoram	0.90	1.06
Nagaland	1.94	2.24
Odisha	2.76	2.58
Punjab	3.37	2.98
Rajasthan	2.42	2.3
Sikkim	0.35	0.44
Tamil Nadu	3.63	3.74
Tripura	1.75	2.03
Uttar Pradesh	3.06	2.86
Uttarakhand	1.20	1.32
West Bengal	2.63	2.42
Andaman and Nicobar Islands	0.47	0.5
Chandigarh	8.93	8.51
Dadra and Nagar Haveli	5.91	5.95
Daman and Diu	7.65	8.46
Lakshadweep	14.23	16.69
Puducherry	6.44	6.07
TOTAL	2.76	2.78

(Source: Indian State of Forest Report, 2013, 2011)

Lakshwadeep, Chandigarh, Kerala are some of the states and UTs where the tree cover is comparatively good. There is no substantial increase in the overall tree cover in the country. Tree cover was 90,849 sq km (2.76% of the total) in 2011 which increased to 91,266 sq km (2.78%) in 2013.

See full report here

Also,  there is a difference between forest cover and tree cover. The aerial “tree cover” does not consider ecological functions like water quality, soils, bio diversity and wildlife habitat. The “tree cover” might include lawns, parks and suburban woodland fringes.

According to WWF, 12-15 million hectares of forest are lost each year, the equivalent of 36 football fields per minute. Read more here