braking

decline, drop, slump

ebb, remission, retreat, wane

flagging, weakening

arrest, check, halt, stoppage

collapse, crash, fall, plunge

halting, stopping

encumbering, hampering, handicapping, hindering, hobbling, holding back, holding up, impeding, inhibiting, obstructing, setting back, tying up (or tieing up)

bottlenecking

arresting, checking, constraining, curbing, reining, restraining

baffling, foiling, frustrating, sabotaging, thwarting