Planning Department of Govt.of India has prepared the policy of protection of grasslands in India. Grassland that are located amidst of protected forest areas ,can be taken for the location of protected grasslands by using remote sensing technique.The Institute for the protection of Grassland is located in Jhasi. I think government has not declared the list of protected grassland in India.
As of now, you may snoof around in the website for site details of Velavedar National Park in Gujarat, and north of Naliya grasslands / Lala Busard Sanctuary (LBS) and south of Narayan Sarovar Sanctuary (NSS). You may try to collect the relevant details on these sites.