Kathmandu, Jan. 27 -- four percent of diesel vehicles, including 20-year-olds still plying the roads in Kathmandu Valley, failed the emission tests carried out by the Kathmandu Metropolitan City in recent days.

According to the Environment Department, under the metropolis, 193 out of 261 buses, micro-buses and Tata pick-up trucks operating on Kathmandu's roads failed the emission test. Only 68 such diesel vehicles passed the test.

Similarly, 20 percent of petrol vehicles (both private and government cars)-14 out of 71-failed the emission test.

"A huge number of diesel vehicles tested recently have been found emitting black smoke well beyond permissible levels," said Jagatman Shrestha, traffic expert adviser at the Kathmandu Metropolita...