Synonyms for Congest:

n.

fill, cork, full, close. congest (noun)
clog, choke, choke off, foul, back up, clog up.

v.

clog (verb)
clog up, block, dam, plug, choke.
hinder (verb)
impede, bung, dam, crimp, frustrate, clog, cramp, curb, oppose, cripple, jam, plug, delay, bar, constipate, deter, check, restrict, complicate, thwart, detain, baffle, paralyze, entangle, entrap, interrupt, snag, drag, encumber, tangle, restrain, burden, counter, brake, snarl, constrain, catch, handicap, bottleneck, mire, choke, hamper, obstruct, fetter, block, foul, impair, resist, stop, inhibit, stay, hamstring, hinder.

Other synonyms:

fill. plug
bung.
stop
choke off.
stop up
plug.
Other relevant words:
close, choke off, clog up, fill, back up, cork.