Answer : 3. "Western disturbances"
Explanation :

1. In northwest India, some weak temperate cyclones from the Mediterranean Sea cause rainfall over Punjab, Haryana, Delhi and western Uttar Pradesh.

2. Western cyclonic disturbances that enter the Indian subcontinent from the west and north-west during the winter months originate from the Mediterranean Sea and are brought into India by the westerly jet stream.

3. On an average, 4-5 western disturbances are formed during the winter season and the distribution of rainfall in each western disturbance is different.

4. Mawat is a Rajasthani word which means "Magh rain". It is very beneficial for crops like wheat etc. It comes from the south-western part.

5. Mawat means "winter rain". This word is mainly prevalent in Rajasthan and other regions of North India. Mawatha usually occurs in the months of December to February. This rain is very beneficial for the wheat crop.