Changes in incentive policy and a crackdown on errant drivers have tilted the balance in Ola's favour in the app cab battle.

A 30-something professional, who swore by Uber for her daily commute from her home off the Bypass to her office near Esplanade for the past year, now banks on Ola. "Lately, Uber has had constant surge pricing of at least 1.3X... often it is 1.5X or more," she said.

Surge pricing on the Uber platform is an indicator of demand outstripping supply and the absence of cabs, at times, in areas where they are usually available.

Abhinav Goel takes an Uber from his home in New Alipore to his office in central Calcutta. "As a rule, there's surge pricing in the mornings. In the evenings, I leave office by 5pm. At that time, I don't get surge pricing," he said.

Later in the evening, Uber cabs are hard to get in the Esplanade-Chandni Chowk area.

Industry experts say drivers switching to Ola has created a vacuum on the Uber platform.

Barun Kumar Singh has two of his cars on the Uber platform. He said recent changes in the driver payment system had lowered a cabbie's share of the profit. "So, many drivers are switching to Ola," he said.

What has made Ola more attractive to drivers is its offer of a Rs 25,000 package over three months if they put the company's stickers on their cars and paint the bumpers green.

"Many drivers are accepting the offer but there are also those who prefer to keep their cars without any branding so they have the flexibility to switch between platforms," Singh said. He has a Hyundai Accent and a Maruti Swift Dzire on the Uber platform.

Many drivers Metro spoke to said some of their colleagues made the switch after Uber started docking a day's pay, following passenger complaints.

"We are losing a day's pay if a passenger lodges a complaint. They are showing us emails from passengers and penalising us for refusals," a driver who has made the switch said. "It's easier to work for Ola as they don't monitor us."

Anand Subramanian, Ola's senior director for marketing and communications,  said: "We don't have any one-star rated drivers in our system. They are off-boarded automatically. We have a robust system of feedbacks and ratings. We respond to emails of our riders, even during the trip."

He credited Ola Micro, which was introduced recently with a rate of Rs 6/km, for the "phenomenal growth" of its fleet.

Ola drivers do 16 to 18 trips a day. With a fixed commission, the more the number of trips, the greater the driver's income, he said.

Uber spokesperson Ruchica Tomar said: "We have seen an impressive uptick in demand with the price cuts introduced in February. We are working round the clock to serve the high demand on our platform. Dynamic pricing kicks in to help serve the demand-supply mismatch and ensure there always is a ride within minutes."

In the season of defection, Uber has been hurt by the polls, too, as the election commission has requisitioned many vehicles.

Dipanjan Purkayastha, who has developed an app to hail regular taxis, said: "Uber is basically reviewing its incentive policy for drivers. In cities like Bangalore, surge pricing has been stopped. Drivers made a fair amount of money under surge pricing. As a result, there is a mass shift to Ola."