It is a great honour and pleasure to be here with you today at Tsinghua University - one of China's leading universities.

Visiting a campus of a Medical School brings back the many memories of my own life as a medical student. Those were shaping years. Filled with learning experiences. Filled with expectations. Filled with aspirations to serve people in need and society as a whole.

Four months ago, I took on the role as Director-General of the World Health Organization. My pledge to the Member States was that WHO would make a difference - in the way we give our advice - in the way we forward research and in the way we contribute to putting health at the core of the global development agenda.

Today, I wish to pay tribute to Tsinghua University for joining me in this vision. You are making a difference. You have selected two critical issues on the public health agenda and shown that you can make a real contribution: in the area of the environment - and in the area of tobacco control.

"A green campus". I like that notion. It offers students first-hand insights into the importance of sustainable development and its true meaning for future generations. It will inform the direction of research and teaching and allow Chinese students to blaze a new trail that will find the right balance between development, growth and protection of the environment.

The rest of the world will undoubtedly gain from this experience.

Then there is tobacco and your decision to show leadership on this critical public health issue. Two days ago, Chinese scientists released new and compelling evidence about the size of the impact that tobacco will have on human health. Worldwide, 3.5 million people will die from smoking this year. That figure is expected to triple to 10 million into the next century. China's share of this tragedy may be huge: Around 2 million of these 10 million dead may be Chinese.

It goes without saying: Tobacco is a primary public health problem and a critical challenge to the public health authorities and the entire health systems in all countries.

Very few medical schools around the world have tobacco as a course of study. As a result, research has shown that medical students do not give much attention to tobacco control, and smoking rates increase even among medical students as they go from freshmen to senior levels.

A "tobacco free" campus here at this university will send a powerful signal across China and beyond. It will carry the message that it is possible to turn back and reduce the impact of one of the greatest emerging health disasters in human history.

The Chinese Government and a wide range of non-governmental agencies have already taken several steps to curb tobacco use. Smoking has been prohibited in several public places. Advertising is banned in electronic and print media, health warnings are present on cigarette packs, and World No Tobacco Day is celebrated each year.

These are all steps in the right direction. We know that in the long run they can make a small but important impact on tobacco use. However, experience from many other countries suggests that stronger approaches are needed: tobacco taxation must be substantially strengthened, smuggling must be curbed, and an enforced ban on tobacco advertising and promotion are needed for sustained success.

I know it from my own country: such economic and legal approaches are difficult. To succeed they need firm political direction and strong public support.

If we take China there is plenty of evidence: we have all the facts to prove the daunting damage caused by tobacco on the health of China's population.

This university can play a lead role in ensuring that effective policies are developed by involving lawyers, economists and behavioural scientists in tobacco control research and training. Health professionals see the problem in all its dimensions every day. They are best placed to begin work on tobacco control. But that is not enough. Their chances of success are limited if they remain alone. A strong coalition of faculty staff working with students could make a real difference to the course of the tobacco epidemic in China. It can be done. And it can begin here.

We know the hurdles and they are many. Across the country, advertising and marketing strategies are used to encourage non-smokers to start. The nicotine content of cigarettes ensures that once they start, many will find it difficult to stop.

A "tobacco free" university can serve as a role model to reverse these trends. It can show that - contrary to what advertising says - to smoke is not the normal thing to do. It can show that smoking is not inevitable. It can show that students who don't smoke are no less "cool". This great university can also show that it can continue to be a leader in many intellectual fields without the support of tobacco companies. Because let us say it loud and clear: that "support" comes with a heavy price tag for society.

Even more significantly, your university can show the links between healthy environmental policies and healthy personal behaviour. A university committed to the environment will document the negative impact of tobacco farming. It will document the impact of lost productivity to the economy because of premature deaths due to tobacco. Based on evidence gathered here, your university will show that a "tobacco free" society can be far more prosperous and healthy than one addicted to tobacco.

Your work will not be easy. Pursuing the public health agenda never was. It is a struggle - and we need to fight it. You can count on the World Health Organization to be on your side in this struggle. In the shaping of our Tobacco Free Initiative we are learning from your ideas and your experience. And our evidence base is there for you to tap.

That is how it should be - sharing of knowledge - sharing of inspiration. As more students pass through these doors and other universities understand your decisions, you may well find yourself leading a movement of students imbued with a strong sense of what constitutes the desired path ahead - for the health and environment of China, and the world.