Provide your best answer for the following question. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The question is: A house is built in a desert, where there is no electricity and very little wind. Which action could lead to operating the electrical appliances in the house that would cause the least amount of environmental pollution?
placing solar panels on the roof of the house
Solar panels installation.