I’ve spent quite a lot of time in India (mainly Hyderabad and Kolkata), and can report that India is much more colourful than Australia. Very garishly so, to my eyes. In clothing, building paint, night-time building lighting (… I found myself sometimes wishing coloured LEDs hadn’t been invented), just about everything imaginable. Weddings can be almost painful in the saturation of colour. But Indian cities are also extremely dusty, so that you only see the full extent of some of the colours in monsoon time when the rain washes it all away—especially the vibrant greens of foliage, which in other seasons often appear completely grey or slightly brown.
(Aside: I live in Victoria, down in the south east of Australia, and foliage colours are generally fairly muted. I’ve been in Darwin once, up in the northern tropical parts of Australia, and found it really weird to see eucalypts and such that clearly felt Australian to my eyes, but in the vibrant tropical greens that I associated (from experience) with Sri Lanka and parts of India.)
I went a little ways into Mexico (Tijuana and Ensenada) and bright colors were so ubiquitous and distracting it was hard for me to find necessary stuff like street signs and business signs. I was looking for a certain business which I was assured I couldn't miss. I drove past it several times, but just couldn't see it because of all the other stuff visually shouting at me.
I lived in Tijuana and Ensenada for a few years and although there may be somewhat more color in Mexico, it is not much, and overall I felt the design fashion to be fairly similar to San Diego where I grew up.
It does depend on where you live. In southern europe red or orange clay roofing and a range of colors on traditional housing including yellow, pink, orange, etc. makes towns appear much more colorful. In parts of Portugal it's also traditional to paint a broad colorful bar along the bottom of whitewashed outer walls and around doors and windows; the color changes from place to place, and it can be black (I've seen that in the Azores) but also blue, green, scarlet, etc.
(Aside: I live in Victoria, down in the south east of Australia, and foliage colours are generally fairly muted. I’ve been in Darwin once, up in the northern tropical parts of Australia, and found it really weird to see eucalypts and such that clearly felt Australian to my eyes, but in the vibrant tropical greens that I associated (from experience) with Sri Lanka and parts of India.)