So I always try to go for Freeze-dried instant coffee ( especially Colombian, like Juan Valdez ), and not the Spray-dried shit.
Edit : I thank max and the OP for enlightening me about the instant coffee manufacture process. It surely appear that Instant coffee has a lot more environmental impact than simple ground coffee because of more processes involved. I have always consumed instant coffee, but were totally ignorant on this part. Dumb of me.
Thanks to the people directing me to the right way, and I will strike out my second point above.