Common feature of environmental problem is that they are both physically Complex and socially complex. They are physically Complex because they involve ecosystem if we put fertilizer on agricultural land and it runs off into rivers a whole range of implications might happen to natural environment and human health.

Social complex becaz environmental problems are caused by range of different people. Not intending to harm the environment but each of their actions contributing to environmental problems. 

Nations play important role in environmental law because they have authority and capacity to develop collective responses in relation to these problems.

Modern environmental law has its roots in 1960 and it wasn't just response to environmental problems it was part of commitment to make societies more just, fair and more democratic

Law is not a magic wand. It's not a case of passing a piece of legislation, signing a Treaty or court deciding a case and environmental problem disappears. What is required is creation of legal framework which ensures the ongoing management of an environmental problem in as fair and just way.

Environmental law is very technically Complex. Environmental lawyers need to know a lot of law and they know how to apply it with nuance and sophistication.

Environmental law has required the expansion of the legal imagination that's because a lot of law that has been developed with environment.

In countries like India and New Zealand legal developments have taken place where the legal rights of the rivers have been recognised.

Important theme in environmental law is environmental justice but environmental justice means many different things it might mean justice between Nations justice within local communities or justice across generations or even from of justice that takes the rights of the earth into account. 

Environmental law is often controversial we might debate whether there is environmental problem or how to solve it. There may be issues with what is a legitimate role of of Government and given the fact that environment law often requires limiting people's behaviour it will awake this resentment but while it is controversial while it is also necessary because we have to live within the carrying capacity of earth.