$4.8 billion worth of projects are now under construction in the Sydney's CBD; according to a new analysis of projects by Corelogic. And it is only going to get busier with a further $3.1 billion of approved projects still to commence and scheduled for completion by 2025. As you walk down Sydney's CBD dusty main streets; you will have no doubts that the work has begun. In the residential space; the largest projects in development are Chinese group Yuhu's 57 story residential tower One Circular Quay and Crown Resorts 71-storey resort tower at Barangaroo. On the commercial front; Lendlease's Circular Quay Tower will become tallest office tower in the city and Macquarie Group's 40-storey tower proposal is promised to be remarkable. The massive construction boom is likely the result of several culminating factors. First; it is the strong fiscal position of NSW government that is reflected in state-led infrastructure projects. In the years following; it is important to ensure that government infrastructure aligns with CBD development. The second reason for the development is tourism and Sydney's attractive lifestyle. Both of which are helping to drive demand for prime harbourside apartments. Hotel and accommodation are worth $1.6 billion and make up the largest component of projects currently under construction in the Sydney CBD. The number of tourists and international professionals that are coming to Sydney steadily increases; partially in response to the rising incomes in south-east Asia; and developers are taking advantage of this opportunity. Last but not least; the third factor contributing to CBD developments is the supply and demand equation. Balance is key; as the Property NSW's Brett Newman says; Getting the balance right is what will make the city sing. The mix of land uses right in the CBD is essential particularly in case of balancing residential versus commercial. Sydney has long been hailed as the most international of Australia's cities;Ms Rampa; Chief Executive of Property; Lendlease; says; However; maintaining this position requires the ability to re-imagine and invest in our built environment. A world-class city can never be said to be complete. So if you're planning to move abroad anytime soon; be aware that if you come back to Sydney five years from now; you might not recognize the city.