Mr.hajay, Chennai, the capital city of Tamil Nadu, is under the consular district of Chinese embassy in New Delhi which has stopped to issue China visa to oridinary passport holders, you should go to the Chinese Visa Application Service Center (CVASC) in New Delhi, you can't send the application to CVASC by courier or registered post, you or you entrust someone else to submit the visa application to CVASC, but you can ask the CVASC to mail back your passport and visa.