Cops are following through on Mayor de Blasio’s pledge to stop locking people up for carrying small amounts of pot.

Police cuffed 18,120 stoners through Oct. 20 — a 40 percent plummet from the 29,906 pot busts in the same period last year, state Division of Criminal Justice records show.

At the same time, tickets for pot violations have surged. Cops handed out 13,081 low-level pot summonses through the end of September — and are on pace for more than 16,000 tickets. The NYPD issued 13,378 pot tickets for all of last year, and 13,316 tickets in 2013, records show.

City Hall ordered cops last year to ticket suspects they caught with 25 grams or less of marijuana instead of arresting them after district attorneys and activists clamored for drug decriminalization.

Still, arrests outnumber tickets citywide, and there appears to be wide variations in enforcement.

Bronx cops in the 45th Precinct in upscale Throggs Neck handed out 415 tickets for marijuana possession and made only 48 arrests in the first nine months of the year. Similarly, Staten Island cops in the 122nd Precinct ticketed 258 people and arrested only 18 suspects, city and state crime data show.

But Bronx cops in the 52nd Precinct in Kingsbridge arrested 720 individuals but ticketed only 168 people in the first nine months of the year. And Queens cops made 259 pot arrests but only ticketed 79 people in South Jamaica’s 113th Precinct, the records show.

Marijuana use in public is still illegal, and the new policy to just issue summons is putting rank-and-file officers in a difficult position, experts say.

“The police are being left in a nowhere land. No matter what they do they’re subject to criticism,” said John Jay criminal justice professor Eugene O’Donnell. “For cops it’s not really about marijuana; it’s about finding marijuana on the way to finding a gun or more serious narcotics.”