Which one among the following stations receives maximum rainfall?

Correct — D, Raipur. Raipur's annual rainfall normal is about 1,290 millimetres, the highest of the four by a clear margin. Bengaluru follows at about 1,078 millimetres, Hyderabad at about 860, and Delhi at about 774. The geography behind the ranking is straightforward: Raipur sits in the Chhattisgarh plain in the upper Mahanadi basin, squarely on the path of the Bay of Bengal branch of the south-west monsoon as it swings up the valley, and it takes almost all that rain between mid-June and early October. Hyderabad lies further inland on the Deccan, on the drier side of the same branch. Bengaluru sits on the Mysore plateau in the rain shadow of the Western Ghats and makes up its total from both monsoons plus heavy pre-monsoon thunderstorms. Delhi is at the far north-western tail of the monsoon, where the current is weakest by the time it arrives.

• (a)Hyderabad — About 860 millimetres a year, on a climate that is tropical wet and dry bordering on hot semi-arid. It is drier than both Raipur and Bengaluru.
• (b)Bengaluru — About 1,078 millimetres — the closest of the three to Raipur, and the reason the item is not trivial. The Western Ghats intercept the Arabian Sea branch before it reaches the Mysore plateau.
• (c)Delhi — About 774 millimetres, the lowest of the four. The monsoon reaches the north-western plain last and leaves it first, and the city sits close to the semi-arid margin.

Rainfall over peninsular and central India falls off with distance from the two monsoon branches and with the shelter of the hills. The Bay of Bengal branch travels up the Ganga plain and also pushes inland along the Mahanadi and Godavari valleys, which is what waters Chhattisgarh and eastern Madhya Pradesh. The Arabian Sea branch dumps its load on the windward Western Ghats and arrives on the Deccan much depleted, which is why interior Karnataka, Telangana and Maharashtra are so much drier than the coast a hundred kilometres away.

Reasoning by position beats trying to recall four numbers. Two of the four cities are on the interior Deccan, one is on the north-western plain, and one is in the central Indian valley belt that the Bay branch reaches with force. Only Chhattisgarh among the four sits in the path of a strong monsoon current without a mountain barrier in front of it. Be careful with Bengaluru — its reputation for pleasant, showery weather makes candidates rank it first, but a moderate total spread over many months is not the same as a large total.

• Raipur receives about 1,290 mm a year, almost all of it between mid-June and early October.
• Bengaluru's annual normal is about 1,078 mm, Hyderabad's about 860 mm and Delhi's about 774 mm.
• Bengaluru lies in the rain shadow of the Western Ghats and draws on both monsoons plus pre-monsoon thunderstorms.
• The Bay of Bengal branch pushes inland along the Mahanadi and Godavari valleys, watering Chhattisgarh.
• Delhi sits at the north-western tail of the monsoon and close to the semi-arid margin of the Northern Plains.

• Ranking Bengaluru first because its weather feels wet through much of the year.
• Assuming a city on a plateau must be drier than one on a plain, regardless of monsoon track.
• Treating Delhi as typical of the Northern Plains, when rainfall on the plain rises steeply eastward.

Asked as a ranking item across four familiar cities, decided by monsoon track and relief rather than by memorised figures.

• practice — not a real PYQ

  Bengaluru receives less rain than the Konkan coast at the same latitude mainly because it lies

  • (a)north of the monsoon trough
  • (b)in the rain shadow of the Western Ghats
  • (c)outside the reach of the Bay of Bengal branch
  • (d)at too high an elevation for convectional rain

  Answer(b) in the rain shadow of the Western Ghats — the Arabian Sea branch sheds most of its moisture on the windward slopes.

• practice — not a real PYQ

  Which branch of the south-west monsoon is chiefly responsible for the rainfall of the Chhattisgarh plain?

  • (a)The Arabian Sea branch
  • (b)The Bay of Bengal branch
  • (c)The retreating north-east monsoon
  • (d)Western disturbances

  Answer(b) The Bay of Bengal branch — it pushes inland along the Mahanadi and Godavari valleys.