Mexico city
Northern Mexico is dominated by the Sonoran and Chihuahuan deserts, which are part of the much larger North American Desert. As such, the region is of arid or semi-arid nature, and water sources are hard to find.
It is not dumped directly, but dragged into the sea by weather the rain and wind, or transported trough water currents. All countries around the Gulf of Mexico (Mexico, the United States, Cuba) contribute to such problem.
It has a huge supply of water. The problem is, it not evenly distributed: while central and southern Mexico have plenty of water, and even the southern lowlands are prone to flooding during hurricane season, most of northern Mexico is dominated by the Sonoran and Chihuahuan deserts. Any effort to bring water to the north is challenging at best, as most of Mexico is crisscrossed by the Sierra Madre mountain ranges (e.g. a water pipeline would be really expensive to build).
Golf of Mexico
Briefly put, one hundred percent of the water in Mexico is in Mexico.
yes
a
Yes. That is why Mexico is considered a developing country.
Overpopulation.
bodies of water and landforms such as the gulf of MEXICO is called
The Gulf of Mexico is Mexico's major body of water on its south eastern border.