Yesterday, I asked whether the dangers in Mexico were deterring migrants from attempting to come to the US.

A new case shows that demand is still strong, and is global. Over 500 undocumented migrants en route to the US were recently found crammed into two trailer trucks, dehydrated and desperately clinging onto ropes strung within the trailers, in the southern Mexican state of Chiapas.

Most of the rescued migrants were from Central America but also came from as far as Nepal, India, China, and even Japan.

It is believed to be the biggest case of human smuggling uncovered in Mexico in recent years. The smugglers were discovered Tuesday after driving through a police checkpoint that had X-ray equipment outside the Chiapas state capital, Tuxtla Gutierrez. There were 240 migrants in one truck, 273 in the other. The migrants said they paid $7,000 each for the journey. Four people have been arrested so far in the case.

"It is the largest rescue of migrants traveling in inhuman conditions," a spokesman from the attorney general's office told the AFP news service.

This “rescue” comes as Mexico has been under fire to improve the security and human rights protections of migrants found crossing through the country – after 72 migrants were massacred last August in a ranch in northern Mexico, allegedly at the hands of the Zetas drug trafficking group. Mexico’s human rights group says that over 10,000 migrants were kidnapped between April and September of last year.

Even as the Mexican government demands fairer treatment of its compatriots in the US, it often turns a blind eye to Central Americans passing through its own country who suffer at the hands of smugglers, drug dealers, and even certified immigration authorities.

The massacre in August put more pressure on authorities to correct what many call a double standard. Lawmakers last month approved a law to “strengthen the protection and security” of migrants.

Last week, immigration directors in seven states were fired after rescued migrants said that regional immigration authorities kidnapped them and handed them over to drug trafficking groups. That agency has now promised to use lie detectors and other confidence testing to clean up the organization.

Ironically, if Mexico does place greater attention on cleaning up its institutions and punishing perpetrators of crime, it may attract those migrants currently scared off – even if that translates into higher chances of getting “caught” crossing illegally through the country.