In region that climates have a high heat or high level of sun light we use nets to protect plants from these high radiation, why using green nets especially?
Green light isn't absorbed by plants and making them appear green. Chlorophyll absorbs radiation in red (longwave) and blue (shortwave) regions of the visible light spectrum.
The green shade net does not allow the direct sunlight to heat the gunny sacks, so together with the evaporating water, they remain cool throughout the day and night. See the link: https://www.thebetterindia.com/93603/summer-heat-cooling-solution-low-cost-easy/