Jali or latticed window - some interesting facts

City palace, jaipur. truecolorsofindia.blogspot.in

Jali Mogul style, Durgah, Uttar praesh.hiveminer.com

A jali or jaali, ( meaning "net") was an important element in Indian architecture of yore with Indo -Islamic influence. The word refers to a nicely perforated ornate stone or latticed screen, usually with a striking geometrical  pattern. In the Islamic architecture,  use of calligraphy in jali may be noticed in many places. Not only does jali increase the aesthetic value of the building but also gives impetus to the beauty of the structure. During the Mogul period, certain innovations were introduced in designing jali. They gave priority to plant-based patterns over the geometric ones that had been around for a long time.  Yet another design was the addition of Petra dura inlay to the surrounds, using marble and semi-precious stones. A good example is Taj Mahal at Agra.
Sidi Saiyad mosque,Ahmedabad.Jali work en.wikipedia.org

The advantage of incorporating jali in the building are manifold. In tropical countries like India, it serves as an air-conditioner, sunlight diffuser, privacy provider and above all energy saver. So, it does the role of many at the same time.  when it comes to addressing environmental comforts based on regions, nothing is more  an effective and down-to-earth simple tool than jali is!!

The following are essential facts of Jali:

01. Jali lowers the temperature indoors by compressing the air passing through the holes. Air, when compressed and released, becomes  cool just like an air-conditioner. 

Jali-lattice window YouTube

02. The diffusion of air  occurs because of increase in velocity when passing through small holes in the screens. So, there is a good penetration of air indoors.  

03. Jali  proves to be effective in hot dry and  humid climate zones.
Humid areas like Kerala and Konkan have larger holes with overall lower opacity than in the case of  dry climate regions of Gujarat and Rajasthan. So, design and size of holes may vary, depending on the climate of the region.

04. Jali provides good ventilation, cuts down and filters the sunlight and increases the movement of air for cross breeze.

05. It reduces  the entry of direct sun rays, haze and glare without affecting the intensity of light and illumination. The result is you get subdued and soft light indoors. This is due to  reduction of the total aperture area of the entire window into  a number of small holes which are of same size or smaller than the thickness of  of material it is built with. Voids of equal depth and height help reduce the glare and ingress.

Taj Mahal, Agra, hiveminer.com

06. Jali is designed in such a way everything outside is visible through Jaali holes but from the outside, nothing is visible inside due to light difference. So, it is best suited for privacy and in the royal households, jali is a common feature in the women's quarters.  Rajput and and Muslim royals adopted this as part of their style of  architecture in Middle ages.

07. Jali with small holes is a good replacement for glass windows because, it allows breeze, reduces haze and glare unlike glass  windows. jali has aesthetic grace without compromising on privacy and utility. 
stone jali, Bibi ka Maqbara, Aurangabad, en.wikipedia.org/

08. Architect Laurie Baker was the one who popularized the use of Jali in modern architecture based on his experience in the state of Kerala.

09. It is true, the old  traditional building practices have declined. However, wooden windows, stone jharokhas, wood-carved screens, pre-molded clay or cement block with voids, open brick wall  and others have found their way occasionally in modern building  constructions that are dominated by solid walls and glass windows.