I’m a citizen of Melbourne. That’s all. Not an economist, nor a politician, a property developer, a demographer. Just a resident with an affection for the city, with all its flaws and idiosyncrasies.

As a citizen, nobody has been able to explain to me clearly why Melbourne, and Australia for that matter, should be absorbing so many new people every year, at a rate far higher than the OECD average, faster than other developed nations, with no feasible plan to cope with it.

The epicentre of what former New South Wales premier Bob Carr calls Australia’s “weird experiment” is Melbourne, my town. Melbourne is on the brink of being a city of 5 million and is growing at record rates (Victoria grew 2.3% in the year to June 2017, way above the national average of 1.6%, itself exceptionally high by developed nation standards).

Dear old Melbourne added a quarter of its population in just 10 years to 2016. At this rate – and projecting population growth is a wobbly science – it will be home to nearly 8 million by mid-century, overtaking Sydney as the country’s largest city.

The impact of this growth is the single most important issue in this town (and no doubt in Sydney, too, and to a lesser extent in Brisbane and Perth). As a lowly if curious citizen, the refusal of any major political party, let alone business groups, for whom the more people the better, to question the pace of growth, even to explain it, is astonishing.

I read report after report which assume with scant elaboration that “there is no alternative” to record population growth. The result is a rumbling backlash, and a justifiable one.

At least this debate is now being held, when for too long it was stuck in our debilitating culture wars, with many progressives wary that questioning immigration rates would give succour to racists.

We can ignore the Pauline Hansons who want to stop Muslims coming here. We can ignore, too, those elements of Tony Abbott’s argument that one reason for easing immigration is because in Melbourne, “ethnic gangs (are) testing the resolve of police.” That’s a dog-whistle.

But we can no longer ignore the tougher questions: the majority of our population growth is due to immigration, particularly in the past decade. Around three quarters of immigrants settle in big cities, where the jobs are.

Those cities, particularly Melbourne and Sydney, are not coping and this circular argument that all we need is better infrastructure and planning and all will be well is arguing backwards. Can we answer first why we want record population growth, and then discuss infrastructure?

The truth is that successive governments, state and federal, have not improved public transport and housing affordability and facilities for the booming outer suburbs anywhere near the rate that is needed for the current population, let alone for the hapless people who arrive each week.

Even with the will – and if the public were willing to pay for it – few state governments could cope with this level of growth. Some of Melbourne’s boom is because people are moving here from interstate – we can’t control that. Governments have little control over how many babies we have. But we can control immigration, which, absent a population policy, is our de facto population policy.

The case for easing immigration is compelling. Even if it’s just for a few years, from an annual permanent immigration intake of around 200,000 to 100,000, to catch up. Even if it’s just so we can take a breath and think about how big this country should be without having it decided for us by default.

Let me offer two examples from the world’s most liveable city, a wry joke if you live here. We are stuck in traffic, long lines of fumes and angry horns, for weeks of our lives. The state government is spending huge amounts on infrastructure, including Victoria’s biggest-ever public transport project, the Metro Tunnel, an $11bn underground rail project that will add five new stations and ease bottlenecks. When will it open? Around 2025.

Will our congestion get better? No way. The prediction is that in two decades, half of all car trips in Melbourne at peak times will be congested, up from a third now. And, according to Infrastructure Victoria, that’s taking into consideration the planned road and rail upgrades.

Let’s take schools. Daniel Andrews’ government a few days ago announced that it would spend nearly $240m to buy land for another 14 schools in suburbs with exploding population.

Education minister James Merlino boasted that 10 new schools opened last year, 11 would open this year and nine next year. That’s great. But the Grattan Institute a couple of years ago estimated that Victoria would need 220 news schools within a decade. The school where Merlino chose to make his announcement, the John Henry Primary School in exploding Pakenham, is at capacity and is taking no new enrolments. It opened just last year.

Businesses and property developers want more and more people because they want bigger markets and more consumers. Most economists seem to like it because they argue it’s great for the economy although, as a more sceptical Ross Gittins pointed out, the productivity commission has found its net impacts to be “negligible”.

And it is true that our migrant intake is skewed towards skilled migrants, with a smaller proportion of family reunions, plus this year, 18,750 people on humanitarian visas. There is nothing wrong with our system. The debate is about the sheer numbers, and whether that is serving us well now.

What is immigration for? Who is it for? The most curious argument in favour of large population growth is that, somehow, Australians – those here for generations and those recently settled – owe it to the rest of the world to populate quickly. Fairfax’s economics correspondent Peter Martin wrote that “the rest of the world has granted us a licence to use this continent on the implicit understanding that we populate it.”

Really? Says who? Fellow Fairfax columnist Jessica Irvine wrote that we need to weigh up the “needs of Australians versus foreigners” in the immigration debate and she had “never placed the hopes and dreams of Australians so far above those of foreigners that their needs become unimportant”.

That’s bewildering. Apart from our humanitarian intake – which is a duty for an affluent country like ours – the primary purpose of immigration is to benefit people who already live here, or at least not to worsen their quality of life. The Productivity Commission made that clear, concluding in a 2016 report that it had “taken the overarching policy objective of immigration to be maximising the wellbeing of existing Australian citizens and permanent residents”.

We have benefited enormously from immigration. We are a land of immigrants. We will, and should, keep growing and much of that growth will be newcomers settling here. That doesn’t mean we shouldn’t pause a tad now. Just for a bit. Just so mug citizens like me can ask a few questions about the city I love.