Slym, 51, seems to have fallen from a higher floor of the hotel in Bangkok, a company spokesperson said, adding that his post-mortem will take place on Monday. The company declined to give more details.
Bloomberg quoted a company spokeswoman to say that Slym was staying in Shangri-La hotel when the incident took place.
A British national, Slym was leading the company at a time when the auto industry was grappling with prolonged slowdown.
He joined the auto major in 2012 as part of a major management overhaul and was responsible for charting out the company's strategy to regain momentum in the domestic market.
Expressing condolence at the sudden demise, Tata Motors Chairman Cyrus P Mistry said: "Karl (Slym) joined us in October 2012, and was a valued colleague who was providing strong leadership at a challenging time for the Indian auto industry. In this hour of grief, our thoughts are with Karl's wife and family."
Slym was visiting Bangkok for a meeting of the Board of Directors of Tata Motors Thailand Ltd, he added.
As part of restructuring exercise Slym last week had announced a voluntary retirement scheme to a section of employees to rationalise costs.
In December, domestic car sales declined 4.52 percent from a year earlier to 1,32,561 units. Tata Motors' sales fell about 42 percent to 6,537 units last month.
Total sales of commercial vehicles were down 25.53 percent to 46,757 units. The company's commercial vehicle sales dropped 45.83 percent to 25,738 units.
Before joining Tata Motors, Slym was the executive vice president, SGMW Motors, China (a General Motors Joint Venture). Prior to that, he was president, managing director and board member of General Motors in India between 2007-11.
For over two decades, Slym was with Toyota and General Motors in various positions across geographies.


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