Most youngsters born in the 21st century would be surprised to find that there was a time when the law of the land mandated every manufacturer to equip bicycles with a "cycle lamp", and every cyclist, apart from having a licence to own a bicycle, had to light it while riding after sunset. Violating the law would result in a traffic cop confiscating the bicycle, and the "offender" had to pay hefty fines at courts the next day, to retrieve his bicycle

Most youngsters born in the 21st century would be surprised to find that there was a time when the law of the land mandated every manufacturer to equip bicycles with a "cycle lamp", and every cyclist, apart from having a licence to own a bicycle, had to light it while riding after sunset. Violating the law would result in a traffic cop confiscating the bicycle, and the "offender" had to pay hefty fines at courts the next day, to retrieve his bicycle.  

In the first half of the 20th century, the lamps used were popularly called "Carbide lamps" which had a lower chamber regularly refilled with calcium carbide, and an upper chamber refilled with water. As the water trickled down and reacted with calcium carbide, it released acetylene gas, which in turn acted as a fuel for the flame, whose brightness could be adjusted by varying the flow of water through a regulator tap. 

By the 1960s, as kerosene was distributed at highly subsidized prices through ration shops, kerosene lamps automatically became popular. Moreover, it avoided the hassles of monitoring water level and carbide levels separately, and sourcing carbide from select shops, whereas kerosene was a household item available everywhere. Interestingly, the purpose of such lamps was not really to help the cyclist find his way in the dark, but was more of an indication of his presence on the road, which ensured his own safety. It was due to the safety factor that the authorities were very strict about enforcing the rule.

However, the biggest issue with such lamps was their vulnerability during winds, which were usually the reason for several arguments with the cops. While the cops would try to confiscate the bicycle for violation, the cyclist would insist that he had indeed lit the lamp which might have been put off by the wind. In such cases, the cop would carefully touch the lamp, and if he felt the warmth, it would vindicate the cyclist's argument, who would then be let-off with a warning. 

By the 1980s, as the prices of magnetic & electrical parts reduced due to mass production, cycle dynamos emerged as the new standard. However, the turn of the century, as bicycles gradually disappeared from roads, the govt quietly abolished such stringent rules related to "cycle lamps", which are now a topic for nostalgia among old timers who still cherish memories of refilling carbide or kerosene, and their regular encounters & arguments with cops over such cycle lamps during their youthful days.