New York CNN Business  — 

New York City has subpoenaed Airbnb for data on roughly 20,000 listings in the area to make sure hosts aren’t breaking local laws about short-term rentals.

In an interview on television station NY1 on Monday, New York City Mayor Bill de Blasio shared his rationale for the subpoena from the Office of Special Enforcement: “If your apartment was rented out every single day, it’s not your apartment anymore. It’s a business.”

“This goes under the category: If you got nothing to hide why are you not coming forward with the information?” he continued. “If Airbnb believes that all of the people it’s working with are doing things right, then why not be transparent.”

A similar subpoena was also issued to vacation rental site HomeAway. They include requests for details about hosts including their addresses, names, contact information, their volume of bookings and amount of money earned.

HomeAway did not immediately respond to a request for comment.

In 2016, New York made it illegal for people to list entire apartments on Airbnb and similar sites for periods of less than 30 days. The law is aimed at cracking down on people turning their homes into hotels and taking potential rental housing off the market while denying the city tax revenue.

In July, New York City Council passed a bill that would have required short-term rental companies turn over information about hosts and rentals every month beginning in February. But one month before it was set to happen, Airbnb and HomeAway won a preliminary injunction that prevented them from having to start releasing data on rental listings.

The companies argued that the law violates their Fourth Amendment rights to be free from search and seizures.

The federal judge’s decision from January suggests that the city already possesses the ability to subpoena Airbnb. “It can use these tools to safeguard its interests while this litigation is pending,” the court filing reads.

In response to the subpoena, Airbnb’s head of global policy Chris Lehane issued a letter to Mayor de Blasio on Tuesday.

In it, Lehane wrote that the company works with more than 500 governments around the world on rules and data sharing.

“It is no secret that we have been vocal supporters of this very approach in New York City — in the form of comprehensive and effective regulations that provide those key protections for New York City hosts and outline clear rules for safety, tax collection, and enforcement against those who would seek to take advantage of our platform to operate illegal hotels,” Lehane wrote.

He also noted that the company has “proactively implemented a stop-gap program of our own,’ in reference to the company’s “One Host, One Home” policy started in 2016 and implemented in San Francisco, Portland and New York. The policy aims to stop individuals from listing and promoting multiple properties on the platform.

Lehane also said the company “offered to work with the City to collaboratively focus enforcement efforts on weeding out large scale commercial operators who seek to circumvent our policies. And while that offer hasn’t yet been accepted, we stand by it.”