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What does कांटे दार mean?

कांटे दार तार : Barbed Wire
Looks like this : http://goo.gl/IwMpq

कांटे : Thorns
कांटे दार : Having thorns attached
तार : Wire
लगाकर : By putting / placing

Hence Barbed wire is made from the mixture of these words and कांटे दार तार लगाकर means "By putting barbed wire"

जिस समय यह काम किया जा रहा था पुलिस ने किसी भी विरोध प्रदर्शन को रोकने के लिए चार मीनार की ओर आने वाली तमाम सड़कों को कांटे दार तार लगाकर बंद कर दिया और पूरे इलाके को अपने घेरे में ले लिया.

Translation : At the time this work was going on, To ward off any display of protest from the public, the police closed off all roads leading to "the Char Minar" (A historical monument in Hyderabad, India) with barbed wire and took the entire area under its control.

P.S. Electricity is बिजली or विद्युत and is nowhere mentioned here.

Explaining Dar :
Dar in Hindi is a suffix that is attached to some nouns that makes them adjectives. The adjective then means that the noun it modifies possesses the quality that is meant by the initial noun. e.g.

Kante + Dar + Noun = the noun has thorns
(कांटे दार पेड़ = a tree that has thorns)

Samajh + Dar + Noun = the noun has understanding / sense / common sense
(समझदार बच्चा = A kid who has common sense)

Vafa + Dar + Noun = the noun has loyalty
(वफादार कुत्ता = A dog who is loyal)

Sometimes attaching dar creates a noun instead :
रिश्तेदार = a Relative = one who possesses relation