New York tenants can use retaliation as a defense to a landlord’s eviction suit. The landlord is presumed to have retaliated against the tenant if the retaliation takes place within six months after:

The tenant complained to the government (e.g. health department or building inspectors);
The tenant sued the landlord to enforce the rights under the lease; or
The tenant recovered a court judgment against the landlord for damages from retaliation, or successfully used retaliation as a defense to an eviction proceeding.

This presumption does not apply if the tenant violates the terms and conditions of the lease, including nonpayment of rent.

The effect of the presumption is that the landlord must give a believable explanation to the court that his actions were not motivated by a desire to retaliate against the tenant.

Retaliation includes:

Landlord’s efforts to evict a tenant by serving an eviction notice or starting a court eviction proceeding; or
Landlord’s substantial change of the terms of the tenancy, including refusal to renew the lease.

This retaliation law is not applicable if:

The dwelling is owner-occupied with less than four units;
The condition from which the complaint or action arose was caused by the tenant, a member of the tenant’s household or a guest of the tenant; or
The lease provides for termination of the tenancy upon a transfer of ownership of the apartment.