The agency was still consolidating the total number of violations as of Tuesday morning, but Artes said the figure had already reached the hundreds.
Despite the widespread violations, the MMDA chief said towing was ruled out because it would have further clogged Metro Manila's busiest thoroughfare.
"There were simply too many vehicles. It would not have been effective if we kept towing them because that would only have caused more traffic," Artes said.
He revealed that MMDA personnel initially managed to tow several vehicles but suspended the operation after some owners confronted enforcement teams.
"When we started, we were able to tow a few vehicles. But when we returned, some of the vehicle owners had become aggressive," he said.
Rather than risk escalating tensions, the MMDA shifted entirely to issuing citation tickets.
The MMDA said it will continue enforcing the no-parking rules through the NCAP and warned motorists that vehicles found illegally parked on major roads remain subject to penalties even without on-site apprehension.
As of 3:45 p.m., the Quezon City Police said about 6,000 rally participants had gathered along EDSA for the Iglesia ni Cristo assembly.