During the winter season, which of the following mainly causes rainfall in the north-western parts of India?

Introduction / Context:

India's rainfall is influenced by various weather systems at different times of the year. While the South West monsoon dominates the summer months, winter rainfall in the north western plains has a different cause. This question checks understanding of the weather disturbances that bring winter rain to areas such as Punjab, Haryana, western Uttar Pradesh, and Rajasthan, which is an important concept in Indian climatology.

Given Data / Assumptions:

• The question focuses on rainfall during the winter season in north western India.
• The options are cyclonic depression, retreating monsoon, western disturbances, and South West monsoon.
• We assume familiarity with basic seasonal wind patterns affecting the Indian subcontinent.
• Western disturbances originate outside the tropics and move into India from the west and north west.

Concept / Approach:

The key concept is that western disturbances are extra tropical cyclonic systems that form over the Mediterranean region and west Asia, and then travel eastwards, entering India from the Pakistan and Afghanistan side. During winter, these disturbances bring cloudiness and precipitation, especially in the north western plains and the western Himalayas. The South West monsoon is active mainly from June to September, and the retreating monsoon affects mostly peninsular India in the post monsoon season. Therefore, western disturbances are the main cause of winter rainfall in north western India.

Step-by-Step Solution:

Verification / Alternative check:

Verification can be done by consulting Indian climatology chapters, which clearly state that western disturbances are responsible for most of the winter rainfall in Punjab, Haryana, and western Uttar Pradesh, and for snowfall in the Himalayas. Weather reports in winter also mention these systems by name when forecasting rain or snow in north western India. In contrast, the South West monsoon and retreating monsoon are associated with other seasons, not winter, making western disturbances the correct and well documented cause.

Why Other Options Are Wrong:

Common Pitfalls:

Students may confuse different types of weather systems and seasons, leading them to pick cyclonic depression or retreating monsoon simply because they are familiar terms related to rain. Another confusion is thinking that the South West monsoon somehow continues into winter. To avoid these errors, clearly associate winter rainfall in north western India with western disturbances, extra tropical systems that are distinct from monsoon circulations.

Final Answer:

The main cause of winter rainfall in the north western parts of India is Western disturbances.