I think you should have put this thread in the off topic section cause i find this subject pretty general.
You're right the world is pretty dirty due to human activities (industries, planes, aumobiles...) particularly when you compare the activities in the ancient times, they didn't produce much pollutions. It's due to technical progress.
But I'm not agree when you say it becomes worse and worse cause - since at least a decade - the different governments try to sensibilize people on the alternative energies (wind, solar enrgy, electric cars...), and are taking actions to reduce the carbon gaz (CO2): incineration of household garbages, encouragement to take bikes or public transports (instead of the cars), etc... The statistics show positive results: For instance, in France (since 1980), we have a significant reduction of the pollution in the cities.
Now in the under developped countries, i believe a huge effort still have to be done.