In a nod to the growing number of South Asian Sikhs in New York City, the Police Department said on Wednesday that it would allow officers who belong to the religion to wear beards and turbans while in uniform — as long as the turbans are blue.

The decision puts the nation’s largest police force among a small group of law enforcement agencies like those of Washington, D.C., and Riverside, Calif., as well as the United States Army, that allow members to have facial hair and wear turbans, often as a religious exception. The Royal Canadian Mounted Police has allowed turbans and beards since the 1990s, and began permitting hijabs this year.

According to the patrol guide of the New York Police Department, officers are prohibited from having beards and nonuniform headdresses, but exceptions can be made for officers who receive a medical or religious accommodation to wear facial hair up to one millimeter in length, essentially stubble.