A student is campaigning for more bins at a spot blighted by mass gatherings and litter after lockdown eased, saying everyone should be "allies tackling a problem".
Isidora Jovanovic, 24, has started a petition to Cardiff council after being disgusted by the litter left by crowds enjoying the sunshine in Cardiff Bay.
Young people were unfairly blamed, she said, and everyone needed to help.
A city councillor said more bins had already been placed around Cardiff.
The steps of the Senedd were littered with empty cans, wine bottles and nitrous oxide canisters this week, leading to what Ms Jovanovic called a "blame game".
The masters student, who lives in Roath, said it was "really upsetting and disappointing" to see the mess people had left behind and even tried to clean some of it up herself.
"There was a lot of alcohol to be honest - glasses and bottles - and the wrapping from fish and chips," she said.
"It wasn't just the bay. Roath was quite filthy, Bute Park as well. You had dog walkers and runners picking up rubbish. I took a couple of bin bags out with me just in case and filled two of them and couldn't collect everything, it was just upsetting.
"It was a very hot day so I think there were more people, so more mess was going to be left. But I think once you've had a few drinks as well people just can't be bothered or just maybe don't think about it."
Her petition calls on Cardiff council to put more bins around the city to "encourage people" to responsibly dispose of their litter, but she said it needed to be a joint effort.
"I think the onus is more on us to clean up our rubbish. Seeing a bin next to you might encourage people to do that. Human nature can be quite lazy sometimes."
She added that hearing young people being blamed for leaving litter was unfair, as "a mixture of ages" were doing the same thing.
"It's a difficult one because I would consider myself a young person. I don't think that the blame game is helpful or productive," she said.
"We are all allies tackling a problem and it's more about coming together with the council too, hopefully.
"If we are to approach it with curiosity as to why this is happening then we can work together to find a solution. When we get this feedback off the people causing the mess and we work with them, then there really is no excuse when the solution is implemented."
In Cardiff Bay on Friday, young people said they were horrified to see the litter and were keen to show they were not doing the same.
Naomi Randall said: "We did see the rubbish and it was pretty shocking. It's pretty disheartening to see how people are treating their local area. "We've been walking - we've done 20km so far today - so we'll be keeping our rubbish, looking out for recycling bins, keeping it in our bags and then dumping it where we can."
Molly, 24, said: "It ruins it for other people as well doesn't it? This area is lovely for families to come out to as well.
"We brought the dog down and you wouldn't want that mess to come down to. I think it's just disrespectful.
"You should bring a bag down with you or there's bins around - you can go and find them. It's just unacceptable."
'Use the bins'
Michael Michael, Cardiff council's cabinet member for clean streets, recycling and the environment, told BBC Radio Wales more than 1,100 large bins had already been added to tackle the litter problem.
"We've had teams over the last two, three days out picking up and cleaning after our visitors. We really want people to enjoy Cardiff's open spaces but what we don't want them to do is litter the place," he said.
"Carry stuff with you, take it home, use the bins."
The sun also shone a light on litter issues in other areas of Wales, such as Powys, this week.
Michael Butterfield, from Llangattock Litter Pickers, said he had seen an increase in the amount of litter in the area since restrictions had started to ease.
"Since the lockdown, we have been seeing more PPE - facemasks predominantly - but the main litter we see out on the verges are drinks - so cans, bottles, single-use cups," he said.
Vale of Glamorgan council issued a warning for those gathering in parks and other open spaces to "bin your litter or take it home" after rubbish and damage from open fires was discovered in beauty spots including Porthkerry Park and Cosmeston Lakes Country Park.
Visiting #Cosmeston or #Porthkerry Park this weekend?🌳— Vale Council (@VOGCouncil) April 2, 2021
🌈 Please help keep our parks enjoyable for all:
✅ No open fires
✅ Cyclists to use only cycle paths or bridleways
✅ Bin your litter or take it home pic.twitter.com/vM62p63qq0