I assume you are going from a much warmer place to Ranchi for the function. At 12 weeks of age, the temperature change will be significant. Woolen vest, sweater, cap and socks is a must. I would still suggest using a cab for going to the function as on a two wheeler, with all the wind blowing the actual temp becomes even less.        In general whenever you are doubtful about whether you have taken adequate precautions for dressing up the baby for winter,  check their toes and fingers. If they are warm and pink, it means the baby is dressed up adequately. If they are not, add on an extra covering. Similarly if the baby is sweating with the clothing you have put, you may remove one covering

cover the head, leg and hands properly with cap socks and mittens , and try to avoid this kind of journey

To cover his head , wear hand , leg . gloves

Cap , socks and gloves Cover  fore head and ears well .