JAKARTA, April 24 (CNN) - A travel ban preventing millions of Indonesian Muslims to travel home from Jakarta came into effect at midnight, on the first day of Ramadan fasting.

Some 27 million people were expected to migrate from Jakarta, the Indonesian capital, back to .their home villages, according to a survey by the Transportation Ministry. This mass migration, called "Idul Fitri mudik," usually happens ahead of the first day of fasting during the holy month of Ramadan.

The travel ban, which will block this migration, includes air, ground, and sea transportation from Jakarta.

Exceptions will be made for emergency services like food or medicine supply, and transportation for paramedics, fire department, and ambulances.

Roads will not be completely blockaded, but there will be checkpoints in place to encourage drivers or travelers to turn back to where they started. These checkpoints will be in place until May 7; after that, people will be subject to a fine or jail time for violating the travel ban, said Transportation Ministry spokesperson Adita Irawati.