Please have a look at these images of my zucchini plant:
What disease is this and what is causing this? What are the solutions to counter this?
Location: India. Weather In May-June: Hot! > 95F days.
That looks like downy mildew. From "The Organic Gardener's Handbook of Natural Pest & Disease Control" (Bradley), p194:
See also Managing Downy Mildew in Cucurbits (Cornell University).
While I think I also see some mildew close to the ground, most of the damage looks like leaf miners - but much, much worse than I've ever had experience with in our cooler climate. I don't find much good guidance for what to do at this point, for this year. When done with the plant, be sure to dispose of it - get rid of the pupae and larvae. Also, clear out nearby weeds that may be hosts.