Why are my tomato plants not producing fruit?

The most common causes: temperatures above 38°C cause flower drop (common April–June in North India); excess nitrogen fertiliser promotes lush growth but no fruit; poor pollination on still terraces; root-bound plants. Too hot? Use shade cloth in peak summer. Feeding too much nitrogen? Switch to potassium fertiliser. Try hand-pollination using a vibrating toothbrush near open flowers.