What should I pack for Mumbai?

Waterproof sandals with a back strap. Not flip-flops. Mumbai's monsoon season runs June through September, and the city receives roughly 2,400mm of rain in those 4 months. Streets in Dadar, Hindmata, and King's Circle flood knee-deep after a heavy downpour. The water hides open drainage grates and smells like wet concrete and old drains. Flip-flops slide off in ankle-deep water and leave your feet exposed. A pair of sport sandals or rubber-soled waterproof shoes will handle both the flooded stretches near Hindmata Bridge and the polished marble floors at Siddhivinayak Temple. Leave the leather shoes at home during peak monsoon. White sneakers are a write-off.

Cotton and linen only. Mumbai holds at 28-33°C with 80-90% humidity for most of the year, and synthetic fabrics cling to your skin like a damp towel by noon. Pack 3-4 loose cotton shirts and 2 pairs of lightweight trousers or a long skirt. You'll need covered shoulders and knee-length bottoms for Haji Ali Dargah, Mount Mary Church in Bandra (founded 1904), and Siddhivinayak Temple. That said, the AC in malls like Phoenix Palladium in Lower Parel and in the local trains' first-class compartments runs aggressively cold. One thin long-sleeve layer handles both the temple dress code and the 18°C chill inside Palladium's food court.

India runs on 230V with Type C, D, and M sockets. Type C (the two-round-pin European plug) fits most Indian outlets, but some older hotels in Colaba and Fort still use the larger three-pin Type D, which no standard Western adapter includes. A universal adapter costs about ₹200 (roughly $2 at 94 INR to the dollar) at Croma in Infiniti Mall, Andheri, but it's safer to bring your own. Pack a portable charger rated at 10,000mAh minimum. A full day from the Gateway of India (built 1924) through Crawford Market and up to Bandra means 8-10 hours of Google Maps navigation and Ola ride-hailing. Your phone battery won't last past 3 PM without backup power.

Skip packing the umbrella. Mumbai's monsoon gusts bend them inside out within 10 minutes, and the sound of cheap umbrella frames snapping is a monsoon-season constant along Marine Drive. Locals carry compact wind-resistant ones from street vendors for ₹150-300. They treat them as disposable. Odomos mosquito repellent cream costs ₹50 at every chemist from Nariman Point to Andheri, cheaper than a single tube of Off! at home. Sunscreen runs ₹200-400 at any Apollo Pharmacy. Cotton kurtas from Fashion Street near Churchgate station sell for ₹200-500 and breathe better in the humidity than any Western t-shirt. They're temple-appropriate too. Worth noting, local chemist chains stock Imodium and electrolyte sachets at ₹15 per ORS packet, so you can pack a lighter toiletry bag than you might expect.