In Karwa Chauth, several things are not allowed during the fasting hours, which typically last from sunrise to moonrise. These restrictions include refraining from food and water, as fasting is a central part of the observance. Additionally, married women are expected to avoid any form of negativity, such as arguing or using harsh language. It’s also customary to abstain from activities like grooming, which includes no makeup, henna application, or even cutting nails during the fast as a sign of devotion and self-discipline.