The government of the Hong Kong Special Administrative Region has cracked down on cross-border parallel trading in infant milk formula to ensure local stores don't run out of stock. The new regulation, starting from March 1, allows a person leaving the city to carry a maximum of two cans, or 1.8 kilograms, of infant formula. Such a person has to be aged 16 years or above and must not have left the city in the last 24 hours. And though offenders face a fine of up to HK$500,000 ($64,469) and two years in jail, 45 people were detained for violating the limit on the first two days of the month alone.

Also, just before Spring Festival, Hong Kong's subway operators reduced the weight of carry-on luggage on trains, from 32 kg to 23 kg, to curb cross-border parallel trading to allay city residents' fears that local stores would run out of infant milk formula.

The two-can limit has become the subject of discussion even at the ongoing annual sessions of the National People's Congress and the Chinese People's Political Consultative Conference.