There are no direct buses connecting Kathmandu and India. However, you can catch a bus from Sunauli-Bhairawa border crossing from Varanasi, Raxaul-Birganj crossing from Patna, Siliguri-Kakarbhitta from Darjeeling, Banbassa-Mahendrenagar from Delhi, and Bahraich-Nepalganj from Lucknow.