Please request adequate information and pictures before attempting a diagnosis.
There are many potential sources of yellowing.

The OP is referring to side growth. Don't remove leaves that do not drop on their own.
You are watering way too much. The pot should dry out and feel light between waterings.
REad the growroom setup sticky in that section about exhaust. You need an exhaust to control temps.

Start a thread in the 'problems' section that includes the troubleshooting form, filled out, and hopefully pictures too.