The number of short-term Airbnbs available in New York City has dropped 70 percent after the city began enforcing a new law requiring short-term rental operators to register their homes. But despite the new requirements, there are still thousands of listings that could be unregistered.

The drop, recorded between August 4 and September 5, the day New York City began enforcing the new law, represents the disappearance of some 15,000 short-term listings from Airbnb. The figures are based on data provided by Inside Airbnb, a housing advocacy group that tracks listings on the platform.

In August, there were some 22,000 short-term listings on Airbnb in New York City. As of September 5, there were 6,841. But it seems some short-term listings have been switched to long-term listings, which can only be booked for 30 days or more. The number of long-term rentals jumped by about 11,000 to a total of 32,612 from August 4 to September 5. These listings do not need to be registered under the new law.

Additionally, Inside Airbnb estimates that around 4,000 rentals in total have disappeared from Airbnb since the law took effect.

That uptick in long-term rentals may show that the law is working, by pushing hosts to offer apartments to those staying in New York City for 30 days or more. The new registration requirement is meant to enforce older rules on short-term rentals in the city, and it comes at a time when New Yorkers face high rents and housing insecurity. Vacation rentals are also known for bringing noise, trash, and danger to residential neighborhoods and buildings.

At a glance, it’s impossible to tell if a listing on Airbnb is registered with the city. Inside Airbnb found that only 28 short-term rentals in New York mentioned having a registration number from the city in their listing, but it’s not immediately clear if those numbers are legitimate, and the number of short-term rentals Inside Airbnb found far outpaces the number the city has registered.

Ultimately, hosts will need to display registration numbers on their listings. New York City has received 3,829 registration applications, reviewed 896 applications, and granted 290 as of Monday, according to Christian Klossner, executive director of the Mayor’s Office of Special Enforcement, which oversees the registration process. The office has denied 90 and returned another 516 seeking corrections or more information.

Airbnb says it began blocking new short-term reservations for unregistered rentals as early as August 14, but did not automatically cancel stays in unregistered apartments before December 1 to avoid disrupting guests’ travel plans. Expedia Group, the parent company of Vrbo, is working with “the city and our partners to meet the law’s requirements and minimize disruption to the city’s travelers and tourism economy,” says Richard de Dam Lazaro, the company’s senior director of government and corporate affairs. Booking.com did not respond to a request for comment.

But amid the chaotic rollout of the new law, a number of listings appear to be falling through the cracks. A search on Airbnb for apartments in New York for more than two guests returns several results that may break the new law. Entire homes are still available for booking, some with enough space for 12 or 14 guests. One, a townhouse in Harlem, has a backyard with a firepit, a living room with a pool table, and five bedrooms, some with multiple beds next to each other, set up hotel-style. It’s listed for around $1,400 per night.