Mexico has emergency services that are accessed through your landline or cellular phone by dialing a three digit number, but not 911. There is not a universal number to reach emergency services no matter where you are in Mexico because each large city or rural area has a unique number.
What we suggest is if you are going to be in a city for a while you will want to get the local numbers and keep them handy or programmed into your cell phone.
If you are planning on driving in Mexico you should map your route and get the emergency numbers that you might need before you go.
The numbers that you would want to have on your list are: