The tower industry worldwide is in a state of flux, with mobile operators looking to slash their infrastructure costs by offloading their own towers, or turning to non-traditional sources of sites. Meanwhile, towercos are extending their reach, either geographically, or into new types of networks such as small cells. All these trends have been highlighted in the past week by events in the US, where Verizon and AT&T are collaborating with a new tower partner; and in India, where American Tower has acquired a major operator as it seeks to become a global force. The US mobile operators have been putting intense pressure on their tower providers to offer them more flexible terms and lower rates, while at the same…