Plz give some advice,and correct the grammar mistake/Hong Kong A-level english writing2010:overcrowding

2010UEQ4 Too much concern on overcrowding
If you like wandering in the streets of Mong Kok, SOHO in Central or Sham Shui Po on holiday, you can get stressed and yell out because of the noisiness and smoke. Regrettably, a tight string seemed to be stuck to your lips, sealed your mouth and reflexing your screams, which make you crazy, make you uneasy.
"It's all overcrowding, a situation that too many people or things in a specific place so that the environment or service system is in tension, causing the problems! "a demographer may explain. It sounds logical, but I would say that pollution problem as well as many others are caused by something else that really seriously damage the quality of life. Though, admittedly, overcrowding may has little effects on those problems. What I mean is that if quality of life means happiness, health, peace and sympathy between people. In such a case, overcrowding should not be the serious or main factor causing the decline in living standard.
Then, what are the root causes of pollution problem, financial and livelihood problem as well as mental problem? It's you! Your overuse of nature resources, your waste of food, your over-purchase of clothes, consumables and one-time-use products, you unscrupulous manners to gain money and promotion, but ,generally indeed, your selfishness ,laziness ,luxury, greediness and inconsideration.
Looking back to the case of Mong Kok or other populous districts, you may think that the air and sound pollution are obviously induced by overcrowding and likely to argue that, in comparison, the pollution problem in uncrowded districts is less serious, hence conclude that overcrowding is the main cause of pollution problem.
Self-study room, however, take for an example. You can hear no noise and, of course, no smoke. What I want to say is that the pollution can be reduced or even be resolved as far as possible, provided that everyone controls himself, behaves well, be considerate and have social ethics.
Though cars are needed for distant transportation, we can choose some eco-friendly transport, such as MTR, electric or eco-source motivated car, which use clean energy and can save fossil oil. Yet, in Hong Kong, in spite of the large amount of public transport provided, richer one always buys a privacy car out of vanity and many others tend to take bus rather than walk or riding a bicycle despite how short the distance is.
Some may cited that overcrowding raises the financial burden of Hong Kong taxpayers as government needs to spend more money and resources to build up facilities and social welfare system. Worse still, the men who are not living in public estate and owning a house will always suffer from the high rent of a living place. Nevertheless, taxpayers should devote themselves to help the weakness. Helping others repay you more than raising your fortune. Moreover, the high rent of a room is due to the fact that Hong Kong government practices high land value policy, the control of market is in hand of a few large developers and Hong Kong people like speculation.
One having a small house can have quality life. As a result, overcrowding leave no place for deterioration of quality life. Secondly, the competition of finding a job can be boosted by overcrowding, but it's not a sufficient condition for increment of unemployed rate. Therefore, overcrowding can no more engender financial problems.
Ridiculously, everyone tended to blame the damage of quality of life on overcrowding as well as insufficient resources, but have they ever