Is Mahjong illegal in Singapore?
No, but there are restrictions...
Under the new Gambling Control Act that was recently announced, the Ministry of Home Affairs (MHA) will now allow physical social gambling like Mahjong to be legalized in Singapore from 1st August 2022 onwards.
What is the reason?
Based on a statement given by MHA, it was mentioned that " this new policy allows the government to more effectively stay ahead of technological and gambling trends, respond more adequately to emerging gambling products, and to take a more holistic and coherent approach to gambling policies ".
What constitutes gambling?

Betting
The making or accepting of a bet, which involves either paying or staking of money or money’s worth on the outcome of a race, competition, sporting event or other event, the likelihood of anything occurring or not occurring, or whether anything is or is not true.
Eg. Betting Money when playing Mahjong
Engaging in gaming activity
Playing a gaming machine, which is a device for betting, participating in a lottery or playing a game of chance.
Eg. Playing slot machines at casinos
Participating in a lottery
Paying money or money’s worth to participate in arrangements, schemes or competitions for the distribution of prizes, which depend on an element of chance.
Eg. Buying 4D/TOTO
What is the Minimum age to gamble Mahjong?
There is no minimum age to gamble Mahjong in a social gathering setting. Provided that you are only gambling with your friends and family at one of the participants' homes. Otherwise, the legal age to gamble is actually 21. If an underaged individual himself is caught committing an offense, the offender is liable to a maximum fine of up to $1500. If the offense is committed by other people in relation to the underaged individual, the offender is liable to a maximum fine of $300,000 or imprisonment of up to 6 years or both.
Under what conditions is Mahjong illegal?

Mahjong is illegal under 3 conditions:
Social gambling in public places
Online gambling
Placing bets with unlicensed gambling service providers
Note: The information above is taken from Singapore Legal Advice
In summary, Singapore is known to be the strictest country in the world. Due to its stern legislative and judicial system, Singapore is one of the safest countries to live in. With the help of heavily enforced laws, citizens will less likely be engaging in gambling activities. Hence, this will act as a preventive measure for gambling addiction. But as mentioned, anybody can learn how to play Mahjong as Mahjong is totally legal in Singapore as long as you follow the rules and regulations set by the government.