New York City's Local Law 18, introduced on Sept. 5, imposes stringent measures on short-term rental hosts, including a requirement for hosts to live in the place they're renting and be present during the guest's stay, and a cap on guest numbers. The law threatens to transform the landscape of short-term rentals in the city and could spell the end of Airbnb's business model there. Airbnb has begun canceling and refunding reservations in unregistered accommodations from Dec. 2 onwards, but some entire apartments for over two people are still available to book beyond Sept. 5, contravening the city’s registration requirements.