You will have around 3 hours journey through flight, this will a bit of exhausting, but not much. So ... you will have 2 X 15 hours to visit delhi. As usual beware of Traffic. :) ...
This is not enough time to know about Delhi, although you can visit some places like Akshardham, Lodhi Garden, Gandhi Memorial - Raj Ghat, Humayuns Tomb and LOTUS TEMPLE. But the most important thing arrange all of the destinations as you get back to airport on time.
Lodhi Gardens is one of the famous park/gardens in Delhi. It is 90 acres in area annd contains many architectures and monuments from the 15th century during the Sayyid and Lodhi dynasties. It is located on the Lodhi Road close to the Safdarjun Tomb. The site is protected by Archeological Survey of India. The reason behind this is that there are few monuments surviving from this era of Lodhis and the Sayyids and this makes it important for preservation. The tomb of Mohammed Shah is visible from the road and it is the first thing to be built here. Sikander Lodhi's tomb is also located here. There are two mosques inside the gardens, the Bara Gumbad and Sheesh Gumbad. The Bara Gumbad ("Big Dome") is a three domed mosque and opposite to it is the Sheesh Gumbad ("glass dome"), containing the remains of an unknown family. Close to Sikander's tomb is the Athpula ("Eight Piered") Bridge built during Akbar's reign.
The garden is very popular for tourists and Delhi-ites alike for picnics, morning exercises, meetings and what not. It is like a green paradise. There is no entrance fee.
Bara Gumbad mosque is a three domed mosque built in 1494 AD built in the Lodhi gardens area during Sikandar Lodi's reign. The interiors of the mosque is decorated with intricate arabesque designs and curvings of floral styles and geometric shaped designs. Its extremely beautiful.
The tomb of Muhammad Shah, the third ruler of the Sayyid dynasty, is situated at the Lodhi gardens and the first thing visible as one enters the garden. During those time, it was customary to have two types of tombs, square and octagonal. The tomb of Mohammad Shah is close to the Bara Gumbad mosque. The tomb is octagon in shape measuring 26'-3" (8m) in diameter. The ceiling is decorated with carvings using circular designs with arabesques and calligraphic motifs. There are eight graves inside, and the middle one is believed to be that of Muhammad Shah.
The National Zoological Park in New Delhi is one of the best zoos in Asia. Established in 1959, the zoo provides a natural habitat to more than 2,000 animals and birds species.
The abundant wildlife are representative of all the continents such as Africa, America, Australia and Asia. Some of the animals found at the National Zoological Park include chimpanzee, hippopotamus, spider monkey, zebras, macaque, hyenas, Fallow deer, Peafowl, and jaguar. The underground Reptile Complex houses a variety of snakes such as King Cobra and Pythons.
A delight of joggers, picnikers and those wishing to romance with their friends or fiancees, Lodi Gardens is a huge area which has room for all kinds of people. Evidence of the sixth city, said to have been built by the Sayyid and Lodi dynasties is found only in the tombs and mosques in the famous Lodi Gardens, which is a favourite point for early morning walkers from the posh south Delhi colonies.
Located right at the back on the northern side of the Lodi Garden lies the biggest tomb - that of Sultan Sikandar Lodi who died in 1517. Sikandar proved to be a capable ruler who was kind to his subjects, and expanded Lodi territory into the regions of Gwalior and Bihar. He made a treaty with Alauddin Hussain Shah and his kingdom of Bengal. He was able to bring his native Afghan nobles under his control, and encouraged trade across his holdings. In 1503, he commissioned the building of the present-day city of Agra.
Entry is free
This tomb lies just north of the Bara Gumbad tomb and mosque and was built during the rule of the Lodi sultans (1451-1526). The facade features traces of blue tiles whilst the inside is decorated with stucco and painted floral patterns and inscriptions. Unlike the Bara Gumbad, this tomb has several graves inside it but the names of the persons buried here are not known.
Entry is free
This tomb is found a few hundred metres in front of you if you enter into the Lodi Gardens from the south entrance. During the Lodi period (1451-1526), tombs were either square or octagonal. This one and the Shish Gumbad to the north are examples of the square type. There are two examples of the Octagonal type within the gardens. This tomb was built during the reign of Sultan Sikandar Lodi (1489-1517) and its interior features beautiful stuccowork and paintings.
Entry is free
This three-domed mosque was built in 1494 during Sikandar Lodi's reign, According to an inscription on it southern interior. The mosque hall is faced with five arched openings and a frontage of bracket and chhaja cornice. Above them are the minarets which are in Tughlaq style. The interior of the mosque is extremely rich in arabesque stucco decoration and paintings consisting of floral and geometrical designs.
Entry is free
Named Lady Willingdon Park when it was laid out in 1936, this artificial garden was created by shifting the village of Khairpur. It marks the south-end of British New Delhi. The garden happens to contain an unusually rich variety of architectural styles ranging from Sayyid and Lodi to Mughal. The present landscaping, carried out in 1968, was done by Joseph Stein, the architect of the India International Centre and modified by a group of Japanese landscape designers. The Lodi Gardens have many species of trees, a Rose Garden, and a Green House, where plants are stored and is a haven for a variety of birds which now make it the "best urban oasis in Asia".
Lodi Gardens (or sometimes Lodhi)
This is one place in Delhi where, once you're in the middle of it, you don't feel like you're in Delhi...which is quite nice (when it all just seems like it's getting too much!)
The gardens are huge, and you could easily spend an hour or two walking around....in amongst the palms trees and other trees you'll come across some old buildings every now and then. They come as some what of a surprise - it's great!