public function disablePayments($observer) {
    $quote = $observer->getEvent()->getQuote();
    $paymentInstance = $observer->getEvent()->getMethodInstance();

    if ($quote) {
        $country = $quote->getShippingAddress()->getCountry();

        if ($country == 'India') {
             if (!$methodInstance instanceof PayTm_Method_Instance) {
                 $observer->getEvent()->getResult()->isAvailable = false;
            }
        }
    }
}