In mathematics there's a Divisibility Rule for 9. It states that a number is divisible by 9 if and only if the sum of its digits is also divisible by 9.
For example:
81 : 8+1 = 9
162 : 1+6+2 = 9
5436 : 5+4+3+6= 18 >(1+8=9)
@ipo_mantra I had also booked a tatkal ticket on 1 June. At 10 AM seats were available but within 2 minutes of procedure the ticket was booked with 58 waiting.
But on the other hand the ticket got confirmed when the chart prepared.