This is the link for the explanation given by Monsanto, is in Spanish but I will translate it.
Title: Pink light in Juana Diaz (this the name of the town) explained
The American seed manufacturer Monsanto today explained a pink lighting that could be seen from the Juana Díaz express.
“This week, some residents may have noticed a pink glow in the night sky of Juana Díaz, near our facilities. These lights are LED growth lights, which are currently being tested in our intelligent greenhouse on the farm of Juana Díaz, “the company explained in written statements.
At the moment, we are working on calibrating the intensity and brightness of these lights. The plan is to use them during the day and some sessions during the sunrise, “they said.
These LED grow lights further advance Monsanto’s smart greenhouse agriculture project for sustainable cotton and soybean conversion projects.
“The greenhouse also includes the complete automation of some processes such as sowing, harvesting and seed production. Other processes follow a combination of automation and the human touch of our skilled.
At least we now know.