the bank document, confirmed air ticket ot hotel booking are not required for business visa application, you just need to prepare the following documents:
(i) Original passport which has more than 6 months left before it expires from the date of application and sufficient blank visa pages.
(ii) One completed Visa Application Form (e-Form / Download) with a recently-taken passport photo; all the items on the application form should be completed neatly with genuine information;
(iii)invitation letter from the organisers of the exihibition
(iv) Covering letter from applicant's company or office with the details of the visiting purpose.
(v) Photocopy of the personal data page of applicant's passport.
if you want to apply for visa in New Delhi or Mumbai, you should submit the visa applcation to Chinese Visa Application Service Center