Sales of electric cars in June plunged 13.5% from the year earlier, having suffered a marginal drop in May, triggering fears that the Indian market may be following global trends. After last year's euphoria, domestic sales slumped to 20% growth in the January-June period to 46,845 units. That's down from a 135% surge in the same period last year, prompting Tata Motors and others to recalibrate expectations.