As a government, I would offer incentives for recycling in both the private and business sectors, rather than force everyone to pay more taxes. I would encourage free enterprise to create a pollution-eliminating, pollution-conscious infrastructure to make recycling and cleaning a routine part of life (the government would not dump thousands of barrels of toxic waste into the ocean to let the salt water eat away at them, for instance).
I would develop trade agreements with countries who had resources toward that end, possibly going as far to enact embargoes to countries whose pollution affected other countries to such an extent as to be a “significant detriment” to people, wildlife, and other countries.
I would have farmers rotate crops so that the soil sustained itself. Composting (including certain paper products) would be a source everybody could contribute to, and draw from. Farmers with livestock would not be assessed additional methane taxes, but would instead be given tax breaks thier first few years in business, until crop farmers and animal farmers could rely more on trade with each other, rather than having the life sucked out of them by government taxation.
The country would be structured not only around replenishing each other by shared and recycled resources, but also by building in such a way that as many people as possible would benefit. Think of it as country-wide profit sharing. Natural resources (wind, sun, water, etc.) would be used as power sources as much as possible.
These ideas are not in-depth, but are intended as inspiration. I didn’t give you enough information to copy and paste, but included enough ideas that you could research and add your own. Since I am not sure what your teacher has in mind, you can take these thoughts and construct what your teacher wants out of them. Good luck :)