Aduana ("Customs") is the Mexican government’s agency charged with the responsibility of controlling imports and exports to and from Mexico.
Duty-Free Limits for people entering Mexico by air and by land year-round limits are $500 USD per person entering Mexico by air, and $300 USD per person by land. As before, personal items (clothing, etc) are exempted from the $300/$500 USD limits. Alcoholic drinks, tobaccos, and gasoline may not be part of the duty-free allowance.
After delivering their customs card, the traveler presses the button on the customs stoplight. If the light turns green the traveler goes forward and exits the customs area, but if the light turns red, the customs officer must verify the correctness of the declaration as compared to the travelers' luggage (and carry on items).