Kathmandu, March 20 The Narcotics Control Bureau has arrested three persons with four kilograms of opium from the outskirts of Kathmandu. Sim Bahadur Titung, 29, Bajra Bahadur Bomjan, 30, and Prem Bahadur Thing, 26, of Makwanpur district were held from Dakshinkali yesterday when they were trying to smuggle the drug into the capital city. DIG Thuile Rai, NCB in-charge, said it was the biggest-ever single seizure of opium in the country. Opium is the dried latex obtained from opium poppy which contains morphine, an alkaloid, which is also used to produce heroin. NCB said high price of opium was the main reason that had led to an increase in the cultivation of the plant. Cultivation of opium plant is rampant in parts of Tarai and central region, mainly in Makwanpur, Rautahat, Bara and Parsa. Opium sells at more than Rs 50,000 per kg in the illegal market of Nepal, but the price depends on buyers and sellers. According a report published by NCB, many farmers, especially in Makawanpur, Udayapur, Baglung, Salyan, Rukum and Dhading districts have been cultivating opium in large swathes of land with technical assistance from experts. Narco cops have taken initiatives to destroy opium poppy before its harvest. However, it is a Herculean task for the law enforcement agency to prevent its cultivation. Geographical remoteness and economic backwardness of the rural people are major factors in illicit cultivation of opium and marijuana, it warned. Due to lack of proper observation of security agencies in remote areas, opium cultivation has become widespread. Most villagers living in extreme poverty without any alternative livelihood sources have been attracted to opium cultivation, resulting in massive decline in the cultivation of traditional crops, it said.