It has taken a mixture of innovative planning, bribery, subsidy and a lot of walking. Most importantly they got there because the way houses were lit previously was so poor. The vast majority of rural Nepalese get their lighting from burning kerosene in tiny lamps - little more than a wick immersed in the fuel. But the weak light this produces comes at a heavy cost. When kerosene burns it fills the room with a nasty mix of particulates and carcinogenic gases - the World Health Organisation estimates that a day's exposure to a kerosene lamp is equivalent to smoking two packs of cigarettes.
Naked flames are also dangerous.
Each year, many Nepali homes burn to the ground when a lamp is toppled. Kerosene lighting has a number of other negative social and economic effects. In the many areas without roads every last litre of the fuel has to be carried, sometimes over many days, by mules, making it expensive and often in short supply. Bad lighting also affects literacy and education. The light from the lamps is so poor that children can only see their schoolbooks if they are almost on top of the flame, directly inhaling even more of the toxic smoke.