I AM coming to the end of a very enjoyable holiday in Hong Kong, spoiled not a little by the existence of litter wherever one travels; not so much in the smart areas and in shopping malls but on the beaches and worst of all in the hills. For instance on the top of every hill in Lantau and the New Territories (and on the paths and stream beds leading to the summits) cans, bottles, cartons and paper are flung around everywhere. On Lantau Peak there is a waste drum and a notice but still litter is strewn around. I suggest that no litter receptacles should be placed anywhere on the hills but a rule be strictly observed by every individual hill walker and lover of the open countryside to bring litter home and to encourage everyone else to do the same. Perhaps in the year ahead (''Year of Litter Clearance'') every visitor to the hills could pick up litter (a good volunteers' project) until all is clear. It would make a fantastic difference to Hong Kong's more beautiful countryside. M. J. STEPHENSON Chester, United Kingdom CITIZENS in Hong Kong have improved a lot in their living habits. For example, by putting litter into the bins. But, have they ever thought about what happens to the rubbish after it has been thrown into the litter bins? The garbage is burnt and this burning system wastes a lot of energy and resources and the gas it emits is hazardous to our health. The Government and its citizens should help out by not just dumping the rubbish into the litter bins, but by recycling and classifying garbage to allow less garbage burning and thus protect the environment. ARRON NARWANI Kowloon