Read 158(3) of MV Act.
158(3) No person shall be liable to conviction under sub-section (1) or subsection (2) by reason only of the failure to produce the certificate of insurance if, within seven days from the date on which its production was required under sub-section (1), or as the case may be, from the date of occurrence of the accident, he produces the certificate at such police station as may have been specified by him to the police officer who required its production or, as the case may be, to the police officer at the site of the accident or to the officer-in-charge of the police station at which he reported the accident:
So possession of insurance certificate is not mandatory while driving vehicle.
Also punishment for driving uninsured vehicle is given in Sec. 196 of MV Act.
196. Driving uninsured vehicle.
Whoever drives a motor vehicle or causes or allows a motor vehicle to be driven in contravention of the provisions of section 146 shall be punishable with imprisonment which may extend to three months, or with fine which may extend to one thousand rupees, or with both.