Which one of the following pairs is not correctly matched regarding peculiarities of Ramganga project?

1. A

   Dam's length - 825.8 metres

   Option (a) claims that the length of the Ramganga dam is 825.8 metres. This statement is factually incorrect regarding the project's official engineering specifications, making it the correct choice for the mismatched pair. Therefore, this option serves as the key.

2. B

   Hydropower - 198 MW generation capacity

   Option (b) states that the hydropower generation capacity of the Ramganga project is 198 MW. This matches the actual installed capacity data associated with the project. Hence, this pair is correctly matched and not the answer.

3. C

   Location - Garhwal (Uttarakhand)

   Option (c) claims that the location of the Ramganga project is in the Garhwal region of Uttarakhand. This correctly identifies the geographical setting where the river and project are situated. Thus, this pair is correctly matched.

4. D

   Irrigated area - 6 lac hectares

   Option (d) states that the irrigated area under the Ramganga project is 6 lakh hectares. This figure accurately reflects the designed irrigation potential of the project. Consequently, this pair is correctly matched and stands valid.

Summary. Official key is (a) because it incorrectly states the dam's length as 825.8 metres. Options (b), (c), and (d) correctly identify the hydropower capacity, geographical location, and irrigated area respectively. Aspirants often confuse project dimensions with catchment area statistics. Careful verification of engineering data helps avoid such errors in examination. This question tests specific factual knowledge of river valley projects in Uttarakhand.