The Bangkok Metropolitan Administration (BMA) wants street vendors licensed, registered and operating in designated areas well away from busy footpaths.
It is imposing order in tourist hot spots such as Siam Square, Sukhumvit, Yaowarat, Nana, Khao San and Chatuchak.
The push has not gone down well with many Thais, including academics and urban planners. The city is being sanitised, they said.
"Bangkok is famous as the city of markets, but now many markets are dead," said British expatriate Philip Cornwel-Smith, author of Very Thai, which explores what is unique about the country.
"Just to treat the markets with eviction after eviction actually does big damage to parts of Bangkok's identity and its reputation internationally."
French tourist David Lago, making his third visit to Khao San Road recently, found it changed.
It was cleaner now, but "boring". "Khao San has lost that charm of being chaotically filled with street vendors. It's empty during the daytime," he said, adding that he would be back after dark, when the hawkers are allowed to set up shop.
A network of street vendors founded to push back against the clean-up effort staged a march to Government House recently, with a list of demands.
Many more attended two events on the issue.
One, called Street Vendor And City: Leaving No One Behind, took place at Chulalongkorn University.
"The management of street vending is a complex issue," Assistant Professor Narumol Nirathron of Thammasat University pointed out.
"The BMA alone can't handle it - it's a matter for the national agenda.
"To achieve United Nations Sustainable Development Goals, the government needs to handle this issue properly, by integrating the work of the economic affairs, security, commerce, tourism and sports and culture ministries."
He and fellow academics from Thammasat, Chulalongkorn, the Thailand Development Research Institute Foundation as well as the Urban and Design Development Centre plan to present an open letter to Prime Minister Prayut Chan-o-cha, asking him to reconsider street-vending regulations designed to "return the pavements to the public".
The government's ultimate intention is to ban street hawkers in 683 areas of the capital where they have long been "temporarily" permitted to do business.
As of last month, they had been targeted in 478 areas, affecting 11,573 vendors in all.
The academics said one reason given for the clean-up was to liberate Bangkok from a "disorderly", "antiquated" and "undeveloped" look.
"In reality, however, a state of disorder - or order, for that matter - also depends on the management by government agencies, while an antiquated or undeveloped look has nothing to do with street vending.
"In the United States and Europe, known for their advanced development, the governments are allowing more street vendors to operate because the authorities are not able to create enough jobs (for everyone).
"Thus, in pursuing the goal to make Thailand modernised and more developed, the government must not leave a number of people behind, as seems to be the case at present."
Assistant Professor Niramon Kulsri-somba, director of the Urban and Design Development Centre, said Bangkok street vending could be sustainably managed and become "a win-win situation".
She and her team are redeveloping the Phaholyothin Soi 9 area with zones for street vendors. "Rather than top-down management, community engagement is the key. We need to get all the stakeholders talking so they can compare their needs and come up with a solution that will satisfy everyone," she said, admitting it will take time.
At the second discussion, Negotiating Bangkok Streets, held at the Bangkok Art and Culture Centre, Ms Trude Renwick, a PhD candidate in architectural history and theory at the University of California, Berkeley, said street-vendor culture was important for a "creative city like Bangkok".
Meanwhile, in response to the petition given to him by the street vendors, Mr Prayut has ordered the BMA and Metropolitan Police to establish committees to address issues with the vendors.