Mobile phone networks have been down in Chennai for three days now, following the deluge. But it has been nearly two days since it rained here, yet most networks are down. Why?

All  mobile operations are run on electric power, including cellphone towers through which our mobile phone connects to its respective network.

The situation in Chennai is presently this: most networks are down, but there are intermittent signals being received at some spots, especially at higher  locations like rooftops. No particular network is down entirely, all networks are working, but only at some spots and not at others.

According to sources in the telecom industry, the situation is worse due to power lines being down.

Most towers are connected to power lines for operation, but they also have battery back-up for up to 8 hrs. Many towers also run on generators which are kept on the ground. Since there is no electricity, towers stopped working. We are well past the 8hr power back up time line, that batteries provide. Generators in many areas are reported to have stopped working also because they were inundated with water.

Cell-phone operators also claim, since some operator sites are not operational, they have been moved to the next best location, which could result in congestion on those phone circuits. 

So to get the networks running, one or all of these things needs to happen – the power supply needs to be restored, batteries have to be recharged or replaced (that's a slow process given that all towers are down), and lastly, generators have to be up and running.

Industry operators say that they are working on solutions to improve the situation.

However, there is some respite, because the government has stepped in and said that all operators have to share their network with other operators. So a user may use any network now. But since far  too many towers are down, it will require time to get them all running.

​Given the adversity the city and its residents have faced in the last few days, a little more time is probably needed to have normal services resume, mobile connectivity included.