See if the supply line is kinked underneath. If that's not it, remove the cartridge and check for debris. While it's removed, turn the water on momentarily to clear the line, etc. Reinstall and test.

This post was edited by homebound on Wed, Aug 21, 13 at 6:19

Thanks for the advice, however the hose below the sink is no kinked. How could it be the cartridge if the water pressure on the hot setting is fine but the cold is not? They are both operated by the same knob and the water flows through the same cartridge.

A tiny bit of debris can block an inlet and reduce flow.

You can remove the cartridge and inspect for debris, run it under water, etc., and reinstall.

Or you try this: Shut off both supply valves, disconnect the cold supply, aim the hose from the sink into a bucket, open the faucet to hot & cold (both), turn on the hot supply briefly, and maybe you will clear some debris into the bucket. Reconnect and see how it works.