Secondly the builder states "Warranty period will be from the date of occupancy".Can we demand that the time will start only when clean OC is issued?
If the builder is stating that the warranty will start from date of occupancy, ask him to provide the proper occupancy certificate from thee competent authority and reiterate this , he cannot claim so, especially in the light of the defects in construction using substandard materials due to which even now the premises are unfit for occupancy.
How to pressurize this builder to give us clean OC and also rectify major defects occurred in complex due to poor quality materials used
The provisional OC by the competent authority especially after the builder having paid the penalty for deviations isa strong proof the premises is still unfit for occupancy. For the defect rectification, if the builder appears to be reluctant, he may be dragged into consumer forum seeking compensation and remedies.