CDS (II) 2023 General Knowledge · Question 105 of 120

Correct — C, Hooghly. India's first underwater metro rail tunnel runs beneath the Hooghly at Kolkata, on the East-West corridor of the Kolkata Metro — the Green Line — between Howrah Maidan and Esplanade. The under-river stretch itself is short, about 520 metres, and was bored by two tunnelling machines that holed through in May and June 2017. Everything about the alignment is dictated by the river: Howrah station is India's deepest metro station at about 33 metres below ground, and a ventilation shaft on the project goes down to about 44 metres, because the tunnels have to dive under the riverbed and climb out the other side. At the September 2023 exam the tunnel was built but carried no passengers; the Howrah Maidan to Esplanade section was inaugurated on 6 March 2024 and opened to the public on 15 March 2024, so a student reading this today can also say that trains now run under the river.

• (a)Yamuna — The Delhi Metro crosses the Yamuna, but it does so on bridges, above the water, not through a tunnel beneath the riverbed.
• (b)Ganga — Tempting, because the Hooghly is a distributary of the Ganga system. But the river the tunnel actually passes under at Kolkata is named the Hooghly, and that is the name the question wants.
• (d)Gomti — The Gomti flows through Lucknow, whose metro has no under-river section. Nothing about India's first underwater metro tunnel is in Uttar Pradesh.

The Kolkata Metro was India's first metro railway, and its East-West corridor was designed to join Howrah, on the right bank of the Hooghly, to Salt Lake Sector V on the left, tying the twin cities into one network. Crossing the Hooghly was the engineering heart of the project. Rather than adding another bridge over one of India's busiest river crossings, the alignment dives under the riverbed — the first time an Indian metro has run beneath a river.

The distractor to watch is 'Ganga'. The Hooghly is indeed part of the Ganga system, a distributary that carries the river's water past Kolkata to the sea, so a candidate who reasons 'the Ganga at Kolkata' is not thinking badly. The question, though, asks under which river the tunnel was constructed, and at Kolkata that river is called the Hooghly; every project document uses that name. The other two options fail on geography rather than nomenclature: the Delhi Metro crosses the Yamuna on viaducts, and the Gomti at Lucknow has no metro tunnel under it. Note the timing carefully — this was an item about a tunnel that existed but was not yet in service when the paper was set.

• India's first underwater metro tunnel runs under the Hooghly on the Kolkata Metro's East-West corridor, the Green Line.
• The under-river stretch is about 520 metres long, between Howrah Maidan and Esplanade.
• The two tunnel boring machines completed their drives in May and June 2017.
• Howrah is India's deepest metro station, about 33 metres below ground, and a ventilation shaft on the project reaches about 44 metres.
• The Howrah Maidan to Esplanade section was inaugurated on 6 March 2024 and opened to passengers on 15 March 2024 — after this exam.

• Answering 'Ganga' because the Hooghly belongs to the Ganga system — the question asks for the river's own name at Kolkata.
• Assuming the Delhi Metro's Yamuna crossings are tunnels; they are bridges.
• Treating the 2017 tunnelling completion as the opening date — passenger service began only in March 2024.

As a one-line 'first in India' infrastructure question, or as a match of projects against the cities and rivers they belong to.

No directly related past PYQ was found.

• practice — not a real PYQ

  India's first underwater metro tunnel lies on which line of the Kolkata Metro?

  • (a)The North-South corridor
  • (b)The East-West corridor
  • (c)The Joka-Esplanade line
  • (d)The Airport line

  Answer(b) The East-West corridor — the Green Line, between Howrah Maidan and Esplanade.

• practice — not a real PYQ

  The Hooghly river is best described as

  • (a)A tributary of the Brahmaputra
  • (b)A distributary of the Ganga
  • (c)An independent west-flowing river
  • (d)A tributary of the Damodar

  Answer(b) A distributary of the Ganga — it carries part of the Ganga's water past Kolkata to the Bay of Bengal.