Squash
As a pollution-free produce, Squash has several benefits: it is relatively easy to grow, its strength against drought and diseases requires minimal pesticides, and can be used to make various condiments (with seasoning, as pancake, or in soup) in summer.  To store squash, slice it thin and completely dry both sides under strong sunlight.  Put them in vinyl bags and store in the shade or inside the freezers. Pick the firm, straight ones without dents, shiny and light green in color.