Kathmandu, June 9 -- Decades after construction began on some of Nepal's largest infrastructure projects, several national pride and strategically important projects remain unfinished despite repeated deadline extensions, rising costs and billions of rupees already spent.

A review of major irrigation, road and transport projects shows a consistent pattern of delays, revised budgets and implementation challenges. Many projects launched between the late 1980s and 2000s are still far from completion, while others have seen costs multiply several times their original estimates.

Officials cite inadequate budget allocations, land acquisition disputes, environmental clearance delays, contractor performance issues and bureaucratic bottlenecks a...