This is a great article on the Guardian website which looks at the motorbike habit of Kathmandu residents and whether or not cycling has a place in the rapidly growing city.
One of the main problems to overcome is the issue of status. Cycling is seen as an inferior mode of transport, even lower than public transport which already suffers from a negative stigma. Recently there have been groups forming to encourage people to ditch motorbikes and shift to bicycles however these groups are in the minority and are facing the tough task of convincing the government and it’s people that change is needed quickly if Kathmandu is serious about tackling the growing issue of air pollution.
You can read more in the article published by the Guardian: http://www.theguardian.com/cities/bike-blog/2014/apr/23/kathmandu-motorbike-habit-cycle-friendly-city-nepal-status