ratnakarnaik wrote:
i request some one used Indian passport after oath ceremony to reply for my mail which will give me some confidence.
The rule is very clear and many have done in the past. Not everyone is in this forum to post their experience.
Nameless, faceless people can write anything in an online forum - so be confident and trust the official rules.
The Indian Citizenship Act, 1955, does not allow dual citizenship. Holding Indian passport/acquiring Indian passport/travelling on Indian passport after acquisition of foreign citizenship constitutes an offence under the Indian Passport Act, 1967, and attracts penalties. The Government of India has prescribed imposition of penalty on a graded scale for the violation of Passport Rules, depending on number of trips made on Indian passport after acquiring foreign nationality (with a three month grace period from the date of acquiring foreign nationality i.e. the date of Naturalisation certificate), renewal of Indian passport after acquiring foreign nationality and retention of Indian Passport for more than 3 years after acquiring of foreign nationality. The date on the Naturalisation Certificate will be treated as date of acquiring foreign nationality and hence, it is mandatory for the applicants to produce his / her Naturalisation Certificate for obtaining Surrender Certificate. 
