You should call 999 when you need immediate help in the following scenarios:

1. a crime is in progress;
2. someone suspected of committing a crime is close by, or you know where the person is;
3. a further crime might be committed;
4. Someone has been seriously injured or is in danger.
5. When you observe suspicious characters, incidents or suspicious parcels left at public areas.

Some examples of this are:-

1. You see someone breaking into your neighbour’s house
2. You see someone behaving suspiciously near a shop
3. You witness to a hit and run traffic accident
4. You noticed someone behaving suspiciously near to a car and the alarm is activated
5. You witness a fight and / or someone is injured
6. A person or people is/are seriously injured or in danger
7. There is a serious risk to life or property
8. You saw an unattended bag in the MRT
9. When any of the above is happening now or has just happened

Please note that this list is not exhaustive.