That's a Pakistan-only car with no safety features [0]. (From the Wikipedia description, "a car with everything manually operated, and with no safety features. The car lacks airbags, ABS, rear window defogger, side air conditioner vents, seat belt reminder and even rear seat belts.") So yes, it's light. You'll also immediately die in a collision, but you get what you pay for I suppose. (The Alto is sold more broadly, but it's still obsolete)
A more spacious Alto that uses some aluminium and magnesium is around 650kg.
Talking about "not-so-heavy" cars...