*Keeping public parks clean is becoming a huge challenge for civic authorities as park goers are leaving mounds of trash behind. They spend a whole day in the park, eat, drink and leave all the trash right there," said Saj Ahmed, an Egyptian marine engineer. New Zealander Amanda Vincent said she loves to go to the park with her kids, but is careful after she spotted leftover burned coal a few times. There is so much rubbish everywhere," said Mehr Farooqui, an Indian housewife.