. . . . . . . . U. S. A. is larger than . . . . . . . . India in area.

'The' is used before the plural forms of names of the countries/states. For example, 'The Netherlands, The United Arab Emirates.' 'USA' is an abbreviation of United States of America. It is a made up of 50 states and hence we use 'The' before 'U.S.A.'
'India' is a proper noun which is in the singular form. We use no articles before the proper nouns, hence we will not use any article before 'India'.