I think you should write HK pollution,
then write some 辦法 to help the sky blue^^(1to3辦法)
Finally,write about blue sky is GOOD~you can write "Clean Air for a Cool Hong Kong"
____________________________________________(全城投入---------------為藍天打氣)
go to www.epd.gov.hk/epd/tc_chi/action_blue_sky/action_blue_sky.html
2007-04-16 15:00:25 補充:
"Clean Air for a Cool Hong Kong"(全城投入---------------為藍天打氣)