Kathmandu, June 30 -- Nepal's Supreme Court has ordered the government to explain why the controversial procurement and operation of Chinese aircraft by Nepal Airlines has never been investigated, nearly a decade and a half after the acquisition process began despite billions of rupees in public losses.

The June 26 order, which came in response to a petition filed a day before, has revived scrutiny of one of Nepal's most controversial aviation procurement decisions-the purchase of six Chinese-built aircraft that were expected to transform air connectivity, particularly to remote mountain regions but instead became a costly financial burden for the national flag carrier.

The six aircraft-four 17-seater Y12E planes and two 56-seater MA60 ...