This new law is designed to create a disincentive towards tenant harassment, by requiring that building owners applying for certain NYC Department of Building (DOB) permits prove that there is no history of harassment in their building.
The NYC Department of Housing Preservation and Development (HPD) has developed a list of 1,000 buildings, with over 26,000 apartments that are included in the CONH Pilot Program. This list will be updated monthly. 
Owners of these buildings are now required to apply for a Certificate of No Harassment before receiving DOB permits for covered work.
Upon application, HPD will conduct an investigation to certify that no tenant harassment has taken place. If HPD determines that there is evidence of harassment, a hearing will be held at the Office of Administrative Trials and Hearings.
Owners denied a CONH will not be able to significantly alter their buildings for five (5) years, unless they provide permanently affordable housing to be built without City subsidy, tax benefits, or inclusionary housing.
Two versions of the CONH program have been in place in Hell’s Kitchen since 1974 and for Single-Room Occupancy buildings (SROs) citywide, but the program was significantly expanded thanks to the City Council’s 2017 CONH legislation. 
The information above is intended to provide limited information only and is not legal advice. The laws relating to tenant harassment, Certificate of Non-Harassment, and evictions in New York are complex. If you are a party to a matter concerning harassment or eviction and otherwise need further guidance in this or a related area of law, SINGH & RANI, LLP can assist you.