to become obstructed

to get bogged down

to stall  - parar (un motor), pararse (dícese de un motor), demorar, andar con rodeos, entretener (a una persona) 

to block  - obstruir, bloquear, atascar, atorar 

to clog  - atascarse, taparse, estorbar, impedir, atascar, tapar 

to stop up

to hinder  - dificultar, impedir, estorbar