Drainage system of society in maharashtra

dear sir i have a flat in vasai virar region on 3rd floor in which a open terrace is attached which is part of the flat and our society is of 3floors and above there is common terrace. in my flat there is a discharge pipe connected to my flat's terrace to discharge water from my terrace and its bottom end is open at ground floor surface. the same arrangement is at common terrace above our floor and there is 2 water pipe connected to discharge water from terrace to ground floor which are also open at ground floor. this arrangement is from building construction and we have made no changes. recently my society's secretary given notice that due to discharge of water from my terrace and common terrace water is logging at ground floor and due to which problems like mosquito and germs has arrised. also he told me that some members from ground floor made complaint against you in this regards. for this problem they enquired and asked me to pay a sum of rs 7000 to connect bottom end of my flats discharge pipe to sewage system. please tell me whether it is legal to charge this as it is outside my flat