Which one of the following places of India experiences the highest atmospheric pressure during the winter season?

Introduction / Context:
Atmospheric pressure patterns over India change with the seasons and are closely linked to temperature distribution. During winter, colder regions tend to have higher pressure, but altitude also plays a crucial role because pressure decreases with height above sea level. This question checks the ability to balance these factors by asking which of the given locations records the highest atmospheric pressure during winter in India.

Given Data / Assumptions:

• The options are Jaisalmer in Rajasthan, Leh in Ladakh, Chennai in Tamil Nadu, Guwahati in Assam, and Shimla in Himachal Pradesh.
• We assume typical winter conditions: cold and dry air over northwestern India and relatively warmer conditions over coastal and low latitude regions.
• We must consider both temperature and altitude effects on pressure.

Concept / Approach:
Atmospheric pressure at a place depends on two major factors: temperature and elevation. Colder air is denser and tends to produce higher pressure, but pressure also decreases significantly with altitude. Leh and Shimla are both high altitude hill locations where the decrease in pressure due to height outweighs the effect of cold temperatures. Chennai is near sea level but remains relatively warm in winter, so pressure is not exceptionally high. Jaisalmer is at a low elevation in the Thar Desert, where winters are cooler than the coastal south but still at or near sea level. This combination of relatively low temperature and low altitude leads to high surface pressure. Among the given options, Jaisalmer therefore has the highest winter pressure.

Step-by-Step Solution:
Step 1: Evaluate Leh. It is very cold in winter but lies at a very high altitude, which causes atmospheric pressure to be substantially lower than at sea level. Step 2: Evaluate Shimla. It is also a hill station at moderate altitude, so its pressure is lower than that of neighbouring plains despite cool temperatures. Step 3: Evaluate Chennai. This coastal city is near sea level but remains warm even in winter, resulting in lower pressure compared to colder inland locations. Step 4: Evaluate Guwahati. It lies at low elevation but has a humid subtropical climate. Winters are mild and not as cold as the northwestern desert interior. Step 5: Evaluate Jaisalmer. Situated in the northwestern desert, it is relatively cold in winter and at low altitude, which together contribute to denser air and higher atmospheric pressure. Hence Jaisalmer ranks highest among the options.

Verification / Alternative check:
Climatological descriptions of India state that during winter a high pressure cell develops over northwestern India and adjoining regions, associated with cold, dry air. Jaisalmer lies in this region and is often cited as having high winter pressure. Leh and Shimla are always noted for low pressure due to altitude, while Chennai and Guwahati do not reach the same density of cold air. This matches the reasoning that Jaisalmer experiences the highest pressure among the places listed.

Why Other Options Are Wrong:

• Leh in Ladakh: Extremely cold but at very high altitude, so net atmospheric pressure is lower than at sea level.
• Chennai in Tamil Nadu: At sea level but warm, so winter pressure is not as high as in colder northern interiors.
• Guwahati in Assam: At low elevation but with relatively milder and more humid winter compared to Jaisalmer.
• Shimla in Himachal Pradesh: A hill station where altitude reduces pressure despite cool temperatures.

Common Pitfalls:
Many candidates are tempted to choose Leh or Shimla simply because they are very cold places, forgetting the strong influence of altitude on pressure. Another pitfall is ignoring temperature and assuming that any sea level coastal city like Chennai might have high pressure, which is not accurate in winter. The key is to remember that the highest winter pressure in India is found over the cold, dry, low elevation northwestern plains and desert, typified by locations like Jaisalmer.

Final Answer:
Among the given options, the place that experiences the highest atmospheric pressure during winter is Jaisalmer in Rajasthan.