That 40rs is applicable if you have negative balance in Account.
It literally says if the balance is negative.
Tht too in fno
Yes Rs 40 but only on Saturdays and Sundays.
Hi @hariom_mishra, the brokerage of Rs. 40 is applicable only if your account at negative balance, as explained in the article 
We need nudge before placing the order.
I dont understand when it said… Its applicable only when your account is negative, how one can place an order when the account is negative?
The simplest way to go negative is during peak margin usage!
The square off’s done then is considered with the revised brokerage
@ShubhS9 correct me if i am wrong
While placing orders if you don’t have sufficient funds in your account the order is rejected.
Account balance can go negative while exiting the existing position. For example, if you’re holding hedged position, the margin requirement is less, now if you close the long leg first, this will increase the margin requirement for holding naked short position. In this case, if there aren’t sufficient funds in your account, it’ll result in negative balance.
Will short margin penalty will also be levied?
The scenario explained above comes under upfront margin scenario, in this case margin penalty is not applicable. Margin penalty is applicable only in case of shortfall in non upfront margins.
This article explains it is detail:
Let’s take a scenario
If my margin requirements increase and it goes negative
1,
I square off my position to bring it within my margin availability. - so for these trade i will be charged a 40 rs. Brokerage.
Since now that I have brought the position within my available margin. Would my further trades for that day will still continue to be charged at 40rs.
Right.
No. Since the margin is not in negative. Brokerage charged will be Rs. 20 for any orders you place, not Rs. 40. Additional brokerage is applicable only for orders placed when there is negative margins in the account.