A business plan that projects returns of HK$1.2 billion for a HK$600 million investment sounds like an excellent deal. Company executives would scrutinise the details to ensure that there were no hidden costs or loopholes. Department heads would argue over where cuts could be made to finance the project. Driving all involved, though, would be the understanding that this was an offer too good to pass up and that it had to be clinched as a matter of urgency. This is, in essence, the deal Hong Kong's government has laid out for four months of public debate with its package of 19 proposals to toughen air quality standards. Unveiling the scheme last Thursday after years of discussion, authorities made plain the costs and benefits. They estimated an investment of HK$600 million was needed to cut polluting emissions, while conceded that this was by no means a definitive figure. In return, our city would get HK$1.2 billion in benefits, ranging from paying less for energy to longer life. If Hong Kong was a company - a matter not too difficult to imagine - approving such a deal would be a no-brainer. Yet as happens so often with wide-ranging proposals, the discussion is quickly turning from how to make it happen and addressing the shortcomings, to whether the community can bear the cost. Some companies are already complaining that they will have no choice but to increase their charges; others contend that they will be forced out of business. A scheme that has been too long in coming and does not offer a timetable could well be delayed and watered-down - as experience has time and again shown. Such was the case with the recently introduced levy on plastic shopping bags and implementation of the final stage of the smoking ban in indoor public places. Until their introduction, Hong Kong for years trailed other parts of the developed world. For the same reason, the recycling of waste is still at a rudimentary stage, idling vehicle engines are permitted and electronic road pricing continues to be off the government's radar. The inaction and part-measures mean that the benefits are either never realised or only partly attained. The temptation to follow this route with the air-quality objectives has to be fought down. Hong Kong is living by 22-year-old standards, and pollution levels have risen markedly in that time. We have since become only too aware of the contribution of emissions from power plants, factories and vehicles to health and climate change. New World Health Organisation guidelines have to be embraced promptly to the highest practicable levels. Among the government's proposals are car-free zones and using more gas to generate power. Highly polluting vehicles would be barred from low-emission zones and phased out. Electricity charges were projected to rise by at least 20 per cent and bus fares by 15 per cent. But our air would be cleaner and healthier. Such measures are investments in Hong Kong's future. They make our city more liveable and attractive to investors and visitors. There are some costs and the community as a whole, or parts of it, will have to pay - exactly who must do so should be the focus of debate. That needs to be a robust, vigorous debate. But the benefits are so far-reaching that there should be no hesitation about putting the measures in place. A publicly listed company that repeatedly gave short shrift to golden investment opportunities would fall foul of shareholders. Questions would quickly be raised about the manner in which the firm was being operated. Investors would take flight. The analogy is one that the government must keep firmly in mind as it steers Hong Kong towards cleaner skies and less dangerous air on our streets.