An ancient script, filled with undeciphered symbols like a headless stick figure and a fish under a roof, continues to puzzle experts. Belonging to the Indus Valley Civilisation, the script remains one of history's biggest linguistic enigmas.
MK Stalin, the Chief Minister of Tamil Nadu, announced a $1 million reward in January for anyone who can successfully decode the Indus script.
Mr Stalin said, "We are still unable to clearly understand the script of the Indus valley civilisation that once flourished."
The Indus Valley civilisation, which flourished over 4,000 years ago across present-day India and Pakistan, was an advanced society with well-planned cities, drainage systems, and thriving trade networks. But unlike contemporary civilisations like Egypt and Mesopotamia, which left behind vast written records, the Indus civilisation's script remains unreadable.
The script, found on pottery and stone seals, is composed of short sequences - most containing only four to five symbols. This limited dataset makes deciphering particularly difficult, as does the absence of a bilingual artifact, like the Rosetta Stone, which helped unlock ancient Egyptian hieroglyphs.
"Not a single sign is deciphered yet," said Nisha Yadav, a researcher at the Tata Institute of Fundamental Research who has spent nearly 20 years studying the script.
"A really important question about the pre-history of South Asia could potentially be settled if we are able to completely decipher the script," Rajesh PN Rao, a computer science professor at the University of Washington who has studied the script for more than a decade, told CNN.
Some experts believe the script belongs to the Dravidian language family, still spoken in South India today. Others argue it has links to Indo-European languages like Sanskrit.
The controversy has sparked strong reactions. Some researchers have received death threats, including Steve Farmer, who co-authored a 2004 study arguing the Indus symbols might not represent a language at all, but rather a set of non-linguistic signs like modern traffic symbols.
Despite these challenges, scholars continue their efforts. Some, like Finnish Indologist Asko Parpola, analyse individual signs for potential meanings. Others, like Mr Rao and researcher Nisha Yadav, use AI models to detect patterns in the script.
With Stalin's reward now in play, amateur cryptographers have joined the race. "I used to get about one or two emails a week. But now, after the prize was sent out, I pretty much get emails every day," Mr Rao said.
