in 2017 before inauguration after spending 3.9 billion rupees and 40 yrs of planning & construction

https://www.financialexpress.com/india-news/pathetic-40-years-rs-389-crore-later-dam-wall-collapses-in-bihar-before-inauguration-by-nitish-kumar/862855/

(BTW, one rupee back in 2008 worthed much more than a 2017 rupee, 3.9 billion rupees probably is grossly understated)