Actions deemed not retaliatory

(a) Notwithstanding the provisions of section 47a-20, the landlord may maintain an action to recover possession of the dwelling unit if: (1) The tenant is using the dwelling unit for an illegal purpose or for a purpose which is in violation of the rental agreement or for nonpayment of rent; (2) the landlord seeks in good faith to recover possession of the dwelling unit for immediate use as his own abode; (3) the condition complained of was caused by the wilful actions of the tenant or another person in his household or a person on the premises with his consent; or (4) the landlord seeks to recover possession on the basis of a notice to terminate a periodic tenancy, which notice was given to the tenant before the tenant's complaint. (b) Notwithstanding the provisions of section 47a-20, a landlord may increase the rent of a tenant if: (1) The condition complained of was caused by the lack of due care by the tenant or another person of his household or a person on the premises with his consent or (2) the landlord has become liable for a substantial increase in property taxes, or a substantial increase in other maintenance or operating costs not associated with his complying with the complaint, not less than four months before the demand for an increase in rent, and the increase in rent does not exceed the prorated portion of the net increase in taxes or costs. (c) Nothing in this section or section 47a-20 shall be construed to in any way limit the defense provided in section 47a-33.