Six tax-exempt cultural institutions taking part in the city’s free Sundays museum initiative for Boston schoolchildren and their families have been relieved of their PILOT payment responsibilities.

The Boston Children’s Museum, Institute of Contemporary Art, Isabella Stewart Gardner Museum, Museum of Fine Arts, Museum of Science and New England Aquarium are no longer part of the city’s Payment of Lieu of Tax Program, according to new PILOT data for last year that was released by the city Friday.

The city had requested PILOT payments from those six cultural institutions for years, but did not do so in fiscal year 2024. Their removal from the program is due to their participation in Boston Family Days, a mayoral initiative that waives museum fees for all city schoolchildren and three of their family members.

“We can confirm that, yes, this is related to Boston Family Days and the agreement between the Mayor’s office and the cultural partners participating in that program,” a spokesperson for Isabella Stewart Gardner Museum said in a Friday email to the Herald.

The five other cultural institutions and Mayor Michelle Wu’s office did not immediately respond to a request for comment.

Wu has advocated for the removal of cultural institutions from the PILOT program in the past. Collectively, nine of those institutions met just 35% of their requested PILOT payment, and contributed less than $500,000 in cash, in FY23.

The three that remain, Boston Symphony Orchestra, GBH, and Longwood Collective, met 100% of their requested PILOT payment last year.

Those nonprofits collectively contributed $396,734 in cash in FY24, and the same amount in “community benefits,” or services, such as college scholarships, health and employment initiatives, that the participating institutions report as providing to the city and its residents.

Under the PILOT program, private institutions with tax-exempt property in excess of $15 million make voluntary payments amounting to roughly 25% of what they would have paid in real estate taxes. Payments are split between cash and community benefits credits.

City data show participating educational, medical and cultural institutions collectively met 76% of their requested $128.79 million PILOT payment last year. Of the $98.52 million total contribution, just $34.85 million was paid in cash, with the remaining amount taking the form of community benefits credits.

While homeowners were hit with double-digit tax hikes this past January, tax-exempt institutions that include the city’s biggest hospitals and colleges failed to pony up $30.2 million of their requested PILOT payment.

The lack of full compliance from many of the participating institutions has long been a source of contention. Advocates and some elected officials have argued that the city’s wealthy nonprofit sector is not paying its “fair share” of city taxes, while that sector has pointed to the community benefits its institutions provide.

The Wu administration is in the process of negotiating with nine of the biggest nonprofits in Boston to ink long-term volunteer PILOT payments to help ease the tax burden on homeowners and businesses.