In my kitchen I have 2 sinks. One in island and the other big sink. The big sink I do not have enough flow of water (hot or cold)> it was good until yesterday suddenly the flow ofwater decreased. I have good pressure in other sink. Please help me

First what brand of faucet do you have, iof you know? Is it a two handle faucet or a single handle faucet? Either way you can take them apart and clean them out if they need it. Have you tried to clean the aerator hat is on the end of the spout, it is possible it has gotten dirty. One more thing, do you live in extremely cold weater and could one of your lines frozen going to that faucet, if so it is possible that some scale broke loose in the line and it may have sotped in the faucet or the aerator.