§ 302. Unlawful occupation. 1. a. If any dwelling or structure be occupied in whole or in part for human habitation in violation of section three hundred one, during such unlawful occupation any bond or note secured by a mortgage upon said dwelling or structure, or the lot upon which it stands, may be declared due at the option of the mortgagee.

b. No rent shall be recovered by the owner of such premises for said period, and no action or special proceeding shall be maintained therefor, or for possession of said premises for nonpayment of such rent.

c. During such period the department in charge of water supply shall not permit water to be furnished in any such dwelling or structure and said premises shall be deemed unfit for human habitation, and the department of health or the department charged with the enforcement of this chapter shall cause them to be vacated.

2. The department may cause to be vacated any dwelling or any part thereof which contains a nuisance as defined in section three hundred nine, or is occupied by more families or persons than permitted in this chapter, or is erected, altered or occupied contrary to law. Any such dwelling shall not again be occupied until it or its occupancy, as the case may be, has been made to conform to law.