It's no cheap to replace a tower and someone has to pay up. The Govt has declined to pay for the tower. The protestors have blamed it on some rouge elements that infiltrated the protest. Some towers were managed by ZTE or some related Chinese entity that is also stuck in a limbo due to the Chinese ban and now they are seeking compensation for damaged towers as a way to recoupe their investments. Which is another reason why Govt wants to break this trend of paying for towers damaged by the protesters.
Ofcourse, none of this news can be authenticated. There are also claims that cell service was blocked in Delhi for the protestors as retaliation for destroying the towers in Punjab by the protestors. As the towers damaged in Delhi seems to collateral to the protest commotions rather than targeted attacks and less in numbers.