n. 25B6; verb
pollution levels decreased : LESSEN, reduce, drop, diminish, decline, dwindle, fall off; die down, abate, subside, tail off, ebb, wane; plummet, plunge.
decrease the amount of fat in your body : REDUCE, lessen, lower, cut, curtail; slim down, tone down, deplete, minimize; informal slash.
increase.
25B6; noun a decrease in crime : REDUCTION, drop, decline, downturn, cut, cutback, diminution, ebb, wane.
increase.