According to the Forest Department officials, 7.5 lakh saplings will be planted in the current financial year besides free distribution of four lakh saplings.

The depleting green cover and increasing levels of pollution has added to the woes of Delhi government which blames rapid urbanisation for it.

Delhi's green cover reduced to 296 sq km in 2011, which is 19.97 per cent of the total geographical area of approximately 1483 sq km, as compared to 2009 when it was 299.58 sq km forming over 20 per cent of the total area, according to a Forest Survey of India report.

The survey report of 2013 is yet to be released, said the state forest department officials.

"It is a major challenge to carry on with the developmental work and maintain the green cover simultaneously. The increasing population demands development and urbanisation posing pressure on the green cover. Although the department is doing the required plantation it cannot ensure that they are provided with land," said A K Shukla, Chief Conservator of Forests.

Further, the growing pollution, according to the forest department officials, is a threat to wildlife.

"There is a possibility that there will be no increase in the population levels of the indigenous wildlife with the increasing levels of pollution and climate change and they can become extinct," said, Shukla adding the census has not yet been done.

He added that there are more than 200 species of migratory birds and 10 species each of animals comprising Nilgai, mongoose, jackal, hyena and porcupines etc in the national capital along with various species of butterflies.