Why is my tomato not setting fruit?

Flower drop without fruit forming has four main causes: temperatures above 38°C or below 10°C (common in North Indian winters); humidity above 90% preventing pollen release (Mumbai monsoon); excess nitrogen keeping the plant vegetative; and lack of pollinators. Fix: switch to high-potassium feed, hand-pollinate with a toothbrush, and use a 30% shade net in peak summer. If temperature is the issue, wait for conditions to moderate.