What kind of documents do I need to bring for a Tourist Visa - Single Entry

Rasika, I think you should apply for a M type instead of L type. Except for the invitation letter, you should provide your valid resident permit for employment in India and introduction letter from your employer, in which it states clearly where you go, who invites you and the invitee's name, address and contact information. Apart from these documents, you should submit your passport, filled application form and a recent passport photo.