Perhaps they are also exported to English-speaking countries?

I've noticed that many manhole covers in the States are marked Made in India. Which perplexes me; it doesn't seem cost-effective to ship something that heavy. I assume that it is so much cheaper to manufacture them in India that it offsets the transport costs.

You'll have to take a look at the manhole covers in London while you're there and see where they came from.
 

I heard, that at the end of the 19th century the uk used the term "made in germany" to mark german "me-too" products on a low quality level (cheap copies) and to distinguish those products from the british originals. Maybe, that's why it is in english.