The correct answer is (a) Rajasthan.
Rajasthan is the first state in India to make rainwater harvesting compulsory for every house. The state government has passed a law in this regard, and all new houses built in the state must have a rainwater harvesting system. The law was passed in 2001, and it has been very successful in conserving water.
Rainwater harvesting is the process of collecting rainwater and storing it for later use. It is a very effective way to conserve water, and it can be used for a variety of purposes, such as irrigation, drinking water, and domestic use.
There are many benefits to rainwater harvesting. It can help to reduce the demand for groundwater, which can help to prevent water shortages. It can also help to improve the quality of water, as rainwater is generally cleaner than groundwater. Rainwater harvesting can also help to reduce flooding, as it can absorb excess rainwater and prevent it from running off into the streets.
There are a few different ways to harvest rainwater. One way is to collect it in a tank or cistern. Another way is to use a roof-top catchment system. Roof-top catchment systems are very effective, and they can collect a lot of rainwater.
Rainwater harvesting is a very important practice, and it can help to conserve water and improve the quality of life. It is a simple and effective way to reduce our reliance on groundwater, and it can help to protect our environment.
The other options are incorrect because they are not the first state in India to make rainwater harvesting compulsory for every house.