Where should I apply for China Visa in India?

I am an Indian citizen and my passport was issued at Patna, Bihar, India. The address I am currently living is also in the same city.

I am going for an exchange programme to Tsinghua University, Beijing and I have a letter from them addressed to the Chinese Embassy, New Delhi. Is it compulsory for me to get the entry permit from Consulate General of China at Kolkata or can I also get it from the Chinese embassy at New Delhi? It'll be a great hassle for me to ask Tsinghua again for the invitation letter. Please reply ASAP.