Explanation:

Desertification, also called desertization, the process by which natural or human causes reduce the biological productivity of drylands(arid and semiarid lands). 

• Declines in productivity may be the result of climate change, deforestation, overgrazing, poverty, political instability, unsustainable irrigation practices, or combinations of these factors. 
• The concept does not refer to the physical expansion of existing deserts but rather to the various processes that threaten all dryland ecosystems, including deserts as well as grasslands and scrublands.
• Some 97.85 million hectares (mha) of India’s total geographical area (TGA) of 328.72 mha underwent land degradation during 2018-19, according to the Desertification and Land Degradation Atlas of India.

This means that 29.7 per cent of the country’s land in that year became degraded, according to the Atlas that was published in June 2021 by the Space Applications Centre (SAC), Ahmedabad.

• SAC comes under ISRO. The atlas was made available on its website recently.
• In 2003-05, 94.53 mha (28.76 per cent of the TGA) underwent land degradation. The number increased to 96.40 mha (29.32 per cent of the TGA) in 2011-13, according to the atlas.
• Besides land degradation, desertification had also increased. Some 83.69 mha underwent desertification in 2018-19. This was greater than the 81.48 mha in 2003-2005 and 82.64 mha in 2011-13 that underwent desertification.
• Land degradation within dry land regions (arid, semi-arid and dry sub-humid regions) is termed as ‘desertification’.
• India is a signatory to the United Nations Convention to Combat Desertification in Paris signed on June 17, 1994.

State-wise break-up 

• Around 23.79 per cent of the area undergoing desertification / land degradation with respect to TGA of the country was contributed by Rajasthan, Maharashtra, Gujarat, Karnataka, Ladakh, Jharkhand, Odisha, Madhya Pradesh and Telangana.
• However, land degradation and desertification was declining in Uttar Pradesh, Rajasthan and Telangana in 2018-2019.

Why desertification

• Loss of soil cover, mainly due to rainfall and surface runoff, was one of the biggest reasons for desertification. It was responsible for 11.01 per cent of the desertification in the country, the ISRO atlas said.
• In 2011-13, water erosion was responsible for 10.98 per cent of desertification in the country. In 2003-05, it was responsible for 10.83 per cent of desertification.
• Vegetation degradation was found to be responsible for 9.15 per cent of desertification in the country. In 2003-05, it was responsible for 8.60 per cent of desertification.

Hence only statement 3rd is correct.