Mexico's ancient canal gardens, Xochimilco, once belonged to the powerful Aztec empire. 

Fast-forward 500 years, nature resides, along with trash.

"I think we all know that humans caused this, and our way of life," said Andres Castillo Martinez, a conservationist. "Mexico City demands water and the water that we had in these canals came from naturally from the hilly areas. It is a basin."

"The urban stain advances with all that it brings. Contamination of the canals with waste—plastics, glass, organic garbage," added Mr. Martinez.

However, groups of young conservations are helping to clean-up Xochimilco.

CGTN's Franc Contreras reports. 

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