Facebook activated the safety check tool so that people in rain lashed Chennai can let their family and friends know that they are and will be safe in the next few days.
Following heavy rains, transport and communication systems have been largely paralysed in Chennai and other districts. Chennai Airport too closed down operations till Thursday morning.
On Wednesday phone lines including helplines either remained busy or were reachable for several times throughout the day because of high call intensity.
As helplines remained busy, people called offices of media houses hoping to reach stranded relatives.
Some people in Chennai who had WiFi connectivity used WhatsApp to communicate.
The social networkâ€™s â€śSafety Checkâ€ť tool asks users if they are in the affected area and enables them to â€śmarkâ€ť themselves as â€śsafe.â€ť Then their Facebook friends will receive a notification. A â€śmark safeâ€ť button lets users mark others as safe, too. There is a comments section in each update, mostly filled with exclamations of relief.
This â€śSafety Checkâ€ť was put in place earlier this year after the deadly earthquake in Nepal in April and later during the Paris attack earlier this month.
The Met department forecasts heavier downpour through the next week, especially in Chennai, Kanchipuram and Thiruvalluvar districts and asked the people to take precautions for the next few days. It warned about the development of anti-cyclone and rainfall throughout the next week. but the intensity would gradually reduce.
There were many requests to contact coming from people in other cities who are worried about their relativesâ€™ and friendsâ€™ wellbeing in Chennai. There are many areas in and around the city that are badly hit with no access to food and water.