What is a contingency crop plan if the monsoon is delayed?

When the monsoon is late, switch to shorter duration and more drought tolerant crops and varieties so the crop can still finish within the shorter remaining season. The core of a contingency plan is matching crop duration to the rain you still have. If sowing is delayed by a few weeks, drop long duration varieties and pick short duration ones of the same crop, or shift to crops that mature fast and tolerate dry spells, such as short duration pulses, millets like bajra and ragi, or castor, depending on your region. Reduce plant population slightly in very dry conditions, do dry sowing only where recommended, and keep seed of an alternate crop ready before the season. Add moisture saving steps like mulching and a protective irrigation if you have any water. Most state agriculture departments and ICAR publish a district level contingency plan that lists exactly which crops and varieties to choose for different lengths of delay, so ask your KVK for your district plan. The key is to decide and keep alternate seed ready before the delay forces your hand.