It is important to remember the three-digit emergency phone numbers of your destination, before you start your journey.
The emergency number differs from country to country, but typically it is a three-digit number so that it can be easily remembered and dialed quickly.
In many countries the public telephone network has a single emergency telephone number (sometimes known as the universal emergency telephone number or occasionally the emergency services number) that allows a caller to contact local emergency services for assistance. These numbers put you through to a switchboard operator and then your call is routed according to whether you need fire services, medical help or the police. (For example UK number 999.) Some countries have a different emergency number for each of the different emergency services; these often differ only by the last digit. (For example in Austria has 112 for all emergency services or Police – 133; Ambulance – 144; Fire – 122.)
The common European emergency number is 112. It is used in all member states of the European Union, United Kingdom, Georgia, Iceland, Liechtenstein, the Republic of Macedonia, Montenegro, Norway, Serbia, Switzerland, Turkey, Ukraine and some other countries in addition to their other emergency numbers or as the main emergency number.
The common American emergency number is 911. It is used in most American countries including the USA and Canada.
For Oceania and Asian Countries, the numbers are different from country to country.
China is Police – 110; Ambulance – 120; Fire – 119
India is Police – 100; Ambulance – 102; Fire – 101
Indonesia is Police – 110; Ambulance – 118; Fire – 113
Japan is Police – 110; Ambulance and Fire – 119
South Korea is Police – 112; Ambulance and Fire – 119
Singapore is Police – 999; Ambulance and Fire – 995
Taiwan is Police – 110; Ambulance and Fire – 119
Thailand is Police – 191; Ambulance – 1669; Fire – 199
Vietnam is Police – 113; Ambulance – 115; Fire – 114
Hong Kong, Macau, Malaysia for all Emergency services – 999
Australia for all Emergency services – 000
New Zealand for all Emergency services – 111
Mobile phones can be used in countries with different emergency numbers. The mobile phone and the SIM card have a preprogrammed list of emergency numbers. When the user tries to set up a call using an emergency number known by a GSM or 3G phone, the special emergency call setup takes place.
The actual number is not even transmitted into the network, but the network redirects the emergency call to the local emergency desk. Most GSM mobile phones have 112, 999 and 911 as pre-programmed emergency numbers, can dial emergency calls even when the phone keyboard is locked, the phone is without a SIM card, or an emergency number is entered instead of the PIN.
It is important to remember the three-digit emergency phone numbers, before you plan your trip you may also want to look up the relevant embassy details for your country and have their contacts in case of emergency.
Wikipedia has a List of emergency telephone numbers for reference, please have a look if you wish to know the numbers for a specific country.