A branch head of a private bank in south Calcutta speaks to The Telegraph:

I could make out that the man was nervous and uncomfortable.

When the man of medium build, in T-shirt and trousers and standing in the queue, approached one of the verification counters to exchange Rs 500 and Rs 1,000 notes, he was asked to provide identity proof. As the branch head, I was overseeing the day's operations, the biggest in my career, standing behind the two tellers.

The man showed a voter ID card but the face was not matching! My colleague at the counter brought it to me and pointed it out. I said we have to refuse.

The man didn't contest. He simply turned around and left with his black bag.

Several such seemingly ghost customers flitted in and out through the day. One of them had a voter card that featured what looked like a photocopied photograph. It was apparent that these people were sent by someone else to get the notes exchanged. All left without uttering a word of protest.

With our account holders, it was another story. Many had come to deposit the demonetised currency notes, not to exchange them, which is the best option.

But some argued with us, asking why they needed to show ID proof when they were legitimate account holders and had their Know Your Customer (KYC) process completed.

I had to explain that our hands were tied because the Reserve Bank of India had sent us the circular. Five or six customers actually demanded to see the circular.

During the day, two fake notes were detected. We informed the customers and impounded the notes. "We had taken payments from parties (clients). How can we say whether it's fake?" one of them asked. The other more or less echoed him.

The preparations for the day had started yesterday. Most of the planning was done - such as seeking additional manpower from other departments like the credit cards division, coordinating with the local police station, getting a portion of the cash delivered and calculating how many people might queue up.

Today, I reached the branch at 7.40am, an hour and 15 minutes earlier than usual. Around 8, we had a meeting for an hour. A consignment of cash arrived.

Our branch is situated on the first floor of the building and customers have to climb the stairs. We deployed one person at the top of the stairs at the entrance, one at the middle and another on the pavement outside. A security guard was sent to the pavement to manage the queue.

The man at the top was asking the one at the bottom to allow five persons up at a time. The person at the middle of the stairs was apprising everyone of the documents they needed to show.

The queue grew longer as the day progressed and there were a few occasions when some of the customers turned impatient.

I had to come down to the road and speak to them.

"It's taking time because documents are being verified. Please bear with us, there are other banks where it's taking double the time," I told them.

If managing queues and calming people down outside the bank was new to me, so was organising food for colleagues. About 15 of them. I had to arrange snacks, tea and coffee for them and also send them for lunch in rotation.

Four police officers visited the bank through the day. They exchanged phone numbers and told us if there was any problem, we could call them.

Finally, at 6pm, the exchange and deposit processes were over but our job was only half done. We could not do any other work today.

In the evening, it was time to check and recheck the documents, count the cash and ensure everything was in place.

Normally, if there is a mistake, we get internal memos from the higher-ups in the bank.

But today, I was wondering whether we would be arrested just in case any forged document or counterfeit note had slipped in unnoticed.