Police yesterday broke up a cannabis growing operation in a Sheung Shui public housing flat, arresting two young women, a mother and her son. The four were aged between 17 and 53. Officers acting on a tip-off seized from a flat in Tin Ming House at Tin Ping Estate five cannabis trees and some seeds worth a total of about HK$10,000, as well as 10 grams of suspected methamphetamine, or Ice, and equipment, worth a total of about HK$8,000.