MANHATTAN, NY — The number of people prosecuted for marijuana possession in Manhattan has plummeted in the three months since a policy shift in the district attorney’s office, statistics released Thursday show.

Manhattan DA Cyrus Vance Jr.’s office stopped prosecuting most low-level pot possesssion and smoking cases on Aug. 1. Under the new policy, only 168 people were arraigned on the relevant marijuana charges in August, September and October combined, down 86.5 percent from 1,246 in the same period last year, according to figures from the DA’s office.

That number included just 28 arraignments in October — a 94 percent drop from the 465 recorded in October 2017, the statistics show.

“The Manhattan D.A.’s Office has exited the marijuana business,” Vance, a Democrat, said in a statement. “Now it’s time for New York State to legalize, regulate, and expunge.”

Vance’s policy change coincided with a new NYPD policy effective Sept. 1 to issue criminal summonses for smoking marijuana in public rather than make arrests, with certain exceptions. The move is meant to address a persistent racial disparity in pot arrests — black and Hispanic people accounted for 86 percent of them last year.

The shifts together have led to a similarly sharp drop in marijuana arrests in Manhattan, Vance’s office said — the number of cases screened last month, a figure correlating with arrests, was down 96 percent compared to October 2017.

A total of 129 cases were screened from August through October, down nearly 92 percent from 1,563 in the same period last year, the DA’s figures show.

Prosecutors have made efforts to limit marijuana prosecutions as state officials have considered whether to legalize the drug altogether in New York. Gov. Andrew Cuomo’s Department of Health recommended setting up a regulated marijuana market for adults and expunging the records of people with past pot convictions in a July report.

Vance had more than 3,000 marijuana cases dating back to 1978 dismissed in September. Brooklyn DA Eric Gonzalez has similarly made an effort to cut down on prosecutions for public pot use and launched a program that could erase up to 20,000 marijuana convictions.

But some advocates say the district attorneys’ policies aren’t always playing out in the courtrooms.

Some New Yorkers are still being “arbitrarily” prosecuted on marijuana-related charges despite a significant drop in the number of pot cases starting in August, according to a report released Thursday by Court Watch NYC, a project through which volunteers observe court proceedings in Manhattan and Brooklyn.

As an example, Court Watch cited differing outcomes in three Manhattan arraignments for marijuana possession on Sept. 24. In two cases, white women defendants were given adjournments in contemplation of dismissal, or ACDs, meaning their cases would be dismissed if they stayed out of trouble for six months. In the third case, a black man was given an ACD but also required to complete three days of community service.

“The DA’s made promises to get elected, and they continue to make promises that look wonderfully progressive in print, but in the courtroom, they are perpetuating the same old racist policies,” Amanda Farrell, a Court Watch volunteer, said in a statement.