Is not having Occupational Certificate (OC) very common for Apartments in Bengaluru?

I have seen multiple apartments where the owners are not given the OC by the builders across Bengaluru and many of them are pending since almost a decade as well that does not allow the residents to even apply e-Khata. In my experience in other cities as well, residents are not liable legally to pay maintenance amount also without OC but here all builders are usually charging the same and people are widely cooperating with them as well but nobody raises any concerns. Further, the RWA takes amount in someone personal account (is that usually the case as well?) and later when they opened an account- how come its a savings account? Should it not be legally a current account?