Tomato leaves curling upward and cupping with tiny white flies underneath

This looks most like tomato leaf curl virus, which is spread by whitefly, and the upward cupping plus thick brittle leaves and stunted bunched growth are classic signs. The virus itself cannot be cured, so the plan is to stop the whitefly from spreading it. Rogue out badly infected plants early, put up yellow sticky traps, spray neem oil for light pressure, and for heavier whitefly use a recommended insecticide such as diafenthiuron or a flonicamid rotated with another mode of action so resistance does not build. Always follow the label dose and pre-harvest interval, and since tomato is eaten fresh respect the waiting period before picking. For the next crop use tolerant hybrids, raise the nursery under insect net, and avoid planting next to old infected fields. Please show a leaf photo to your KVK or horticulture officer to confirm before you spray.