While travelling to the Indian metropolitan cities like Delhi, Mumbai, Kolkata, Bangalore and Pune, you may find the general dressing sense fairly liberal and westernized. You may find wearing jeans, skirts, capris, t-shirts, tees and even tank tops/ spaghetti tops quite comfortable to wear. In fact, anything reasonably modest is perfect wear in Indian metropolitans. However, in any case, it is recommended to keep a shrug and/ or a scarf handy in your carry bag that can come handy to cover your shoulders and/ or head, whenever you feel the need, and get away with scanty clothes that you may be wearing to begin the day without a hitch.
It is further recommended to keep your packing minimal and light. If there is a need, you can always purchase clothes from local shops, considering that clothing in India is pretty economical and you'd be able to add some authentic Indian ethnic wear to your wardrobe to mingle in the crowd and enjoy tourism better.
Though men could go for shorts too, but considering that your itinerary could as well include places of worship like temples, gurudwaras or mosques, or small towns/ villages – it is advisable to wear full-length trousers at such places. Females are advised to wear long skirts, full length or, at least, knee length trousers etc., tops with full sleeves or half sleeves and carry a stole/ scarf to readily cover your head at such places. As you are also required to remove your footwear at the entrance of each place of worship, it is recommended to wear flip flops or floaters for more comfort at places of worship.
Speaking of footwear, it is always more comfortable to wear flats over high heels in India, wherever you go. It is highly recommended to pack a pair of trainers or sneakers and flip flops in your bag along with a pair of fancy shoes that you may have set your heart on for going to elite restaurants/ malls/ parties etc.