The Tatkal scheme of Indian railways is an option which allows customers to book a ticket a day before the actual journey, buy paying a premium price, after normal seats are exhausted. Previously Tatkal booking online used to be possible from 8am three days prior to journey. But recently Tatkal booking has been changed to allow booking only on the eve of the journey, and only after 10 a.m. What this implies is that Tatkal booking from the comfort of your homes is no longer a viable option when tickets are a scarcity. It is quite likely that tickets are exhausted by the time booking opens online.
It is not uncommon to see long queues of people outside railway booking counters even as early as 5 a.m. Scenes like below are quite common:
Unfortunately, Indian railways are not helping remedy the situation by enforcing restrictions on Tatkal booking online.